125876 + Interview Questions in General QA

1.	……… is an autoimmune disorder affecting the action of acetylcholine.
Answer» Myasthenia gravis is an autoimmune disorder affecting the action of acetylcholine.

Discussion

2.	The deficiency of vitamin D causes ……in children.
Answer» The deficiency of vitamin D causes Rickets in children.

Discussion

3.	The deficiency of vitamin D causes ……… in adults.
Answer» The deficiency of vitamin D causes Osteomalacia n adults.

Discussion

4.	Read the extracts given below and answer the questions that follow:Ausable was for one thing fat. Very fat. And then there was his accent. Though he spoke French and German passably, he had never altogether lost the American accent he had brought to Paris from Boston twenty years ago "You are disappointed," Ausable said wheezily over his shoulder.1. Who is Ausable ? Who is he talking to?(i) Ausable is a secret agent. He is talking to Fowler, the receptionist.(ii) Ausable is a secret agent. He is talking to Fowler, the other secret agent.(iii) Ausable is a secret agent. He is talking to Fowler, a reporter.(iv) Ausable was a secret agent. He is talking to Fowler, a painter.2. How is Ausable different from others of his class?(i) Ausable is different from other secret agents as he is very fat . Moreover, he lives in a room where there is no environment of romantic and thrilling adventure.(ii) Ausable is different from other secret agents because he doesn't believe in disguising himself for the important missions and lives in his home.(iii) Ausable is different from other secret agents because he is very simple and lives in a small hut where there is no environment of romantic and thrilling adventure.(iv) Ausable is different from other secret agents because he keeps four bodyguards around him and lives in small fIat with dull surrounding and no thrill.3. Why is Fowler with him?(i) Fowler was his friend who just came to the hotel to catch up with him after so long.(ii) Fowler is a reporter and a romantic writer. He wanted the details of some unusual happening from Ausable.(iii) Fowler is a painter who just came to draw the portrait of Ausable.(iv) Fowler was a reporter who came to a get together with Max and Ausable.4. Who got fooled and by whom in the story?(i) Fowler was fooled by Max in the story.(ii) Ausable was fooled by Fowler.(iii) Max got fooled by Ausable in the story.(iv) Ausable got fooled by Max in the story.5. Why is Max in Ausable's room?(i) Max came to invite Ausable to a party.(ii) Max came to meet both Ausable and Fowler because they all were good friends.(iii) Max came to get hold of his pistol stolen by Ausable.(iv) Max came to Ausable's room sneakily to get hold of the important papers.
Answer» 1. (iii) Ausable is a secret agent. He is talking to Fowler, a reporter. 2. (i) Ausable is different from other secret agents as he is very fat . Moreover, he lives in a room where there is no environment of romantic and thrilling adventure. 3. (ii) Fowler is a reporter and a romantic writer. He wanted the details of some unusual happening from Ausable. 4. (iii) Max got fooled by Ausable in the story. 5. (iv) Max came to Ausable's room sneakily to get hold of the important papers.

4.

Read the extracts given below and answer the questions that follow:Ausable was for one thing fat. Very fat. And then there was his accent. Though he spoke French and German passably, he had never altogether lost the American accent he had brought to Paris from Boston twenty years ago "You are disappointed," Ausable said wheezily over his shoulder.1. Who is Ausable ? Who is he talking to?(i) Ausable is a secret agent. He is talking to Fowler, the receptionist.(ii) Ausable is a secret agent. He is talking to Fowler, the other secret agent.(iii) Ausable is a secret agent. He is talking to Fowler, a reporter.(iv) Ausable was a secret agent. He is talking to Fowler, a painter.2. How is Ausable different from others of his class?(i) Ausable is different from other secret agents as he is very fat . Moreover, he lives in a room where there is no environment of romantic and thrilling adventure.(ii) Ausable is different from other secret agents because he doesn't believe in disguising himself for the important missions and lives in his home.(iii) Ausable is different from other secret agents because he is very simple and lives in a small hut where there is no environment of romantic and thrilling adventure.(iv) Ausable is different from other secret agents because he keeps four bodyguards around him and lives in small fIat with dull surrounding and no thrill.3. Why is Fowler with him?(i) Fowler was his friend who just came to the hotel to catch up with him after so long.(ii) Fowler is a reporter and a romantic writer. He wanted the details of some unusual happening from Ausable.(iii) Fowler is a painter who just came to draw the portrait of Ausable.(iv) Fowler was a reporter who came to a get together with Max and Ausable.4. Who got fooled and by whom in the story?(i) Fowler was fooled by Max in the story.(ii) Ausable was fooled by Fowler.(iii) Max got fooled by Ausable in the story.(iv) Ausable got fooled by Max in the story.5. Why is Max in Ausable's room?(i) Max came to invite Ausable to a party.(ii) Max came to meet both Ausable and Fowler because they all were good friends.(iii) Max came to get hold of his pistol stolen by Ausable.(iv) Max came to Ausable's room sneakily to get hold of the important papers.

Answer»

1. (iii) Ausable is a secret agent. He is talking to Fowler, a reporter.

2. (i) Ausable is different from other secret agents as he is very fat . Moreover, he lives in a room where there is no environment of romantic and thrilling adventure.

3. (ii) Fowler is a reporter and a romantic writer. He wanted the details of some unusual happening from Ausable.

4. (iii) Max got fooled by Ausable in the story.

5. (iv) Max came to Ausable's room sneakily to get hold of the important papers.

Discussion

5.	Read the extracts given below and answer the questions that follow:Ausable moved to an armchair and sat down heavily." I am going to raise the devil with the management this time, and you can bet on it, " he said grimly.1. Who is the speaker and the listener?(i) The speaker is Fowler and the listener is Ausable.(ii) The speaker is Ausable and the listener is both Fowler and Max.(iii) The speaker is Ausable and the listener is Max.(iv) The speaker is Max and the listener is Ausable and Fowler.2. What does Ausable means in these lines?(i) According to him, somebody had entered his room through balcony the first time and he would not tolerate that. So he would raise the issue of privacy and security with the management.(ii) According to him, somebody had entered his room, the third time through the balcony. So he would raise the issue of privacy and security with the management.(iii) According to him, somebody had entered his room the second time through balcony's he would raise the issue of privacy and security with the management .(iv) According to him , somebody has entered his room for the first through the balcony. So he would raise the issue of privacy and security with Fowler.3. Who is the author of the story?(i) Robert Arthur wrote the following story.(ii) Adrienne Rich wrote the following story.(iii) William Shakespeare wrote the following story.(iv) Ben Johnson wrote the following story.4. Why was Ausable grimming?(i) Ausable was grimming at the late service of the waiter because he was very hungry at that point of time.(ii) Ausable was grimming to make Max believe that here is a balcony in his room and somebody entered in his room through that balcony earlier.(iii) Ausable was grimming because he was annoyed to look at the dirty hotel room because he loved cleanliness.(iv) Ausable was grimming at Max because he came without informing him in his room.5. Describe the appearance of Ausable?(i) Ausable was a very thin man.(ii) Ausable was a quite tall man.(iii) Ausable was quite a very short man,(iv) Ausable was very fat man.
Answer» 1. (ii) The speaker is Ausable and the listener is both Fowler and Max. 2. (iii) According to him, somebody had entered his room the second time through balcony s he would raise the issue of privacy and security with the management. 3. (iv) Robert Arthur wrote the following story. 4. (v) Ausable was grimming to make Max believe that here is a balcony in his room and somebody entered in his room through that balcony earlier. 5. (iv) Ausable was very fat man.

5.

Read the extracts given below and answer the questions that follow:Ausable moved to an armchair and sat down heavily." I am going to raise the devil with the management this time, and you can bet on it, " he said grimly.1. Who is the speaker and the listener?(i) The speaker is Fowler and the listener is Ausable.(ii) The speaker is Ausable and the listener is both Fowler and Max.(iii) The speaker is Ausable and the listener is Max.(iv) The speaker is Max and the listener is Ausable and Fowler.2. What does Ausable means in these lines?(i) According to him, somebody had entered his room through balcony the first time and he would not tolerate that. So he would raise the issue of privacy and security with the management.(ii) According to him, somebody had entered his room, the third time through the balcony. So he would raise the issue of privacy and security with the management.(iii) According to him, somebody had entered his room the second time through balcony's he would raise the issue of privacy and security with the management .(iv) According to him , somebody has entered his room for the first through the balcony. So he would raise the issue of privacy and security with Fowler.3. Who is the author of the story?(i) Robert Arthur wrote the following story.(ii) Adrienne Rich wrote the following story.(iii) William Shakespeare wrote the following story.(iv) Ben Johnson wrote the following story.4. Why was Ausable grimming?(i) Ausable was grimming at the late service of the waiter because he was very hungry at that point of time.(ii) Ausable was grimming to make Max believe that here is a balcony in his room and somebody entered in his room through that balcony earlier.(iii) Ausable was grimming because he was annoyed to look at the dirty hotel room because he loved cleanliness.(iv) Ausable was grimming at Max because he came without informing him in his room.5. Describe the appearance of Ausable?(i) Ausable was a very thin man.(ii) Ausable was a quite tall man.(iii) Ausable was quite a very short man,(iv) Ausable was very fat man.

Answer»

1. (ii) The speaker is Ausable and the listener is both Fowler and Max.

2. (iii) According to him, somebody had entered his room the second time through balcony s he would raise the issue of privacy and security with the management.

3. (iv) Robert Arthur wrote the following story.

4. (v) Ausable was grimming to make Max believe that here is a balcony in his room and somebody entered in his room through that balcony earlier.

5. (iv) Ausable was very fat man.

Discussion

6.	What causes Gouty arthritis in humans?
Answer» Gouty arthritis is caused by excessive formation of uric acid.

Discussion

7.	I knew you were going to leave before you know yourself. Who said it and how did he know it? Substantiate with example from the text.
Answer» Mr Koch was Albert’s Maths teacher. He was genuinely interested in Albert. Yuri told Albert to get a written reference from him. He willingly gave Albert the reference he wanted. He made it clear that Albert was ready to enter a college or institute for the study of higher mathematics. Mr Koch regretted that Albert was leaving the school. His logic was correct. A reference is usually asked when one leaves. Albert is puzzled. There are more surprises In-store for Albert. He is summoned by the headteacher before Albert’s request for Interview. The headteacher does not want Albert to stay there any longer. Perhaps the issue might have figured In the staff council. The Maths teacher was discreet. He did not reveal the confldentìal discussion. He gave plausible reasons for his observation.

7.

I knew you were going to leave before you know yourself. Who said it and how did he know it? Substantiate with example from the text.

Answer»

Mr Koch was Albert’s Maths teacher. He was genuinely interested in Albert. Yuri told Albert to get a written reference from him. He willingly gave Albert the reference he wanted. He made it clear that Albert was ready to enter a college or institute for the study of higher mathematics. Mr Koch regretted that Albert was leaving the school. His logic was correct. A reference is usually asked when one leaves. Albert is puzzled.

There are more surprises In-store for Albert. He is summoned by the headteacher before Albert’s request for Interview. The headteacher does not want Albert to stay there any longer. Perhaps the issue might have figured In the staff council. The Maths teacher was discreet. He did not reveal the confldentìal discussion. He gave plausible reasons for his observation.

Discussion

8.	Calculate the number of atoms per unit cell of silver which crystallizes in fee lattice.
Answer» Contribution of particles from one corner = 1/8 Contribution from 8 corners = 1/8 × 8 = 1 Contribution from 6 face centres = 1/2 × 6 = 3 Total number of particles present in the unit cell of the crystal = 1 + 3 = 4 Number of atoms present in one unit cell of Ag = 4.

Discussion

9.	Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous. (i) Tetra phosphorus deioxide (P4O10) (ii) Ammonium phosphate (NH4)3PO4 (iii) SiC (iv) I2 (v) P4 (vi) Plastic (vii) Graphite (viii) Brass (ix) Rb (x) LiBr (xi) Si
Answer» Ionic – (NH₄)₃PO₄ and LiBr Metallic – Brass and Rb Molecular – P₄O₁₀,I₂ P₄ Network (Covalent) – Graphite, SiC, Si Amorphous – Plastics

9.

Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous. (i) Tetra phosphorus deioxide (P4O10) (ii) Ammonium phosphate (NH4)3PO4 (iii) SiC (iv) I2 (v) P4 (vi) Plastic (vii) Graphite (viii) Brass (ix) Rb (x) LiBr (xi) Si

Answer»

Ionic – (NH₄)₃PO₄ and LiBr

Metallic – Brass and Rb

Molecular – P₄O₁₀,I₂ P₄

Network (Covalent) – Graphite, SiC, Si

Amorphous – Plastics

Discussion

10.	What are the various types of mixtures ?
Answer» Mixtures are of two types: (I) Homogeneous – A mixture is said to be homogeneous if its composition is uniform throughout. (II) Heterogeneous – A mixture is said to be heterogeneous if its composition is not uniform throughout.

10.

What are the various types of mixtures ?

Answer»

Mixtures are of two types:

(I) Homogeneous – A mixture is said to be homogeneous if its composition is uniform throughout.

(II) Heterogeneous – A mixture is said to be heterogeneous if its composition is not uniform throughout.

Discussion

11.	(a) ‘Stability of a crystal is reflected in the magnitude of its melting points’. (b) The melting points of some compounds are given below: Water = 273K, ethyl alcohol = 155.7 K, Diethyl ether = 156.8K, Methane = 90.5K. What can you say about intermolecular forces between these molecules?
Answer» (a) Higher the melting point, greater are tire “forces holding the constituent particles together and hence greater is the stability. (b) The intermolecular forces in water and ethyl alcohol are mainly hydrogen bonding. Higher melting point of water than alcohol shows that hydrogen bonding in ethyl alcohol molecules is not as strong as in water molecules. Diethyl ether is a polar molecule. The intermolecular forces present in them are dipole -dipole attraction. Methane is a non-polar molecule. The only forces present in them are the weak Vander Waal’s forces (London / dispersion forces).

11.

(a) ‘Stability of a crystal is reflected in the magnitude of its melting points’. (b) The melting points of some compounds are given below: Water = 273K, ethyl alcohol = 155.7 K, Diethyl ether = 156.8K, Methane = 90.5K. What can you say about intermolecular forces between these molecules?

Answer»

(a) Higher the melting point, greater are tire “forces holding the constituent particles together and hence greater is the stability.

(b) The intermolecular forces in water and ethyl alcohol are mainly hydrogen bonding. Higher melting point of water than alcohol shows that hydrogen bonding in ethyl alcohol molecules is not as strong as in water molecules. Diethyl ether is a polar molecule. The intermolecular forces present in them are dipole -dipole attraction. Methane is a non-polar molecule. The only forces present in them are the weak Vander Waal’s forces (London / dispersion forces).

Discussion

12.	What is Mixtures? Give the types.
Answer» A mixture is a combination of two or more elements or compounds in any proportion so that the components do not lose their identity. Air is an example of a mixture. Mixtures are of two types: Homogeneous Mixture and Heterogeneous Mixture

12.

What is Mixtures? Give the types.

Answer»

A mixture is a combination of two or more elements or compounds in any proportion so that the components do not lose their identity. Air is an example of a mixture.

Mixtures are of two types:

Homogeneous Mixture and

Heterogeneous Mixture

Discussion

13.	Define the terms Homogeneous mixtures.
Answer» Homogeneous mixtures have the same composition throughout the sample. The components of such mixtures cannot be seen under a powerful microscope. They are also called solutions. Examples of homogeneous mixtures are air, seawater, gasoline, brass etc.

13.

Define the terms Homogeneous mixtures.

Answer»

Homogeneous mixtures have the same composition throughout the sample. The components of such mixtures cannot be seen under a powerful microscope. They are also called solutions.

Examples of homogeneous mixtures are air, seawater, gasoline, brass etc.

Discussion

14.	Mark the correct order of decreasing acid strength of the following compounds.(i) e > d > b > a > c(ii) b > d > a > c > e(iii) d > e > c > b > a(iv) e > d > c > b > a
Answer» (ii) b > d > a > c > e

Discussion

15.	An alkoxide is a stronger base than hydroxide ion Justify.
Answer» Due to the presence of an alkgzl group, higher electron density is found in alkoxide ion. Both the ions can act as base by donating the lone pair of electron on the oxgen atom present in the ionic species. As in alkoxide ion O atom is linked with electron releasing alkyl group, the enhanced electron density on O atom due to +I effect of alkyl group makes it more basic than -OH ion.

Discussion

16.	Which of the following is most acidic?(i) Benzyl alcohol(ii) Cyclohexanol(iii) Phenol(iv) m-Chlorophenol
Answer» (iv) m-Chlorophenol

Discussion

17.	Which of the following species can act as the strongest base?
Answer» The correct answer is (ii)

Discussion

18.	Phenol is less acidic than ______________.(i) ethanol(ii) o-nitrophenol(iii) o-methylphenol(iv) o-methoxyphenol
Answer» (ii) o-nitrophenol

Discussion

19.	Which of the following compounds will react with sodium hydroxide solution in water?(i) C6H5OH(ii) C6H5CH2OH(iii) (CH3)3 COH(iv) C2H5OH
Answer» (i) C₆H₅OH compounds will react with sodium hydroxide solution in water.

Discussion

20.	Diethylether does not react with sodium. Why?
Answer» Because Diethylether does not contain any active hydrogen.

Discussion

21.	Write the different stages in writing the chemical formulae of compounds formed by the combination of magnesium ion (Mg3+) with phosphate ion (PO3-4) and carbonate ion (CO32-)
Answer» Mg²⁺ PO^3-₄ Mg²⁺ CO^2-₃ Mg₃(PO₄)₂ Mg_2/2 (CO₃)_2/2 MgCO₃

21.

Write the different stages in writing the chemical formulae of compounds formed by the combination of magnesium ion (Mg3+) with phosphate ion (PO3-4) and carbonate ion (CO32-)

Answer»

Mg²⁺ PO^3-₄

Mg²⁺ CO^2-₃

Mg₃(PO₄)₂

Mg_2/2 (CO₃)_2/2

MgCO₃

Discussion

22.	What would be the sum of the charges of the positive ions and negative ions in a ‘molecule’ of NaCI?
Answer» 1⁺ + 1^- = 0 (zero)

Discussion

23.	What are the method of writing chemical formulae of salts?
Answer» While writing the chemical formula, first write the symbol of the positive ion and then the symbol of the negative ion. Write the numbers indicating the charge of each ion as subscripts after interchanging them. Simplify the subscripts and write them in the smallest whole-number ratio.

Discussion

24.	Why slats are neutral in nature?
Answer» Salts are electrically neutral. The sum of the charge of the positive ions and negative ions in a salt will be zero.

Discussion

25.	Read the extracts given below and complete the statements that follow :“He holds him with a skinny hand ‘there was a ship’, quoth he,‘Hold off ! Unhand me, grey-beard loon’ !”(a) Who are the two speakers in the above lines ?(b) Why does one person use his skinny hand to hold the other person ?(c) Explain the meaning of ‘grey-beard loon’. (d) What does the word ‘quoth’ mean ?
Answer» (a) The two speakers are the Ancient Mariner and the Wedding Guest. (b) The Mariner did not want the Wedding Guest to leave. (c) The Mariner is very old and looks and behaves like a crazy person. (d) Said.

25.

Read the extracts given below and complete the statements that follow :“He holds him with a skinny hand ‘there was a ship’, quoth he,‘Hold off ! Unhand me, grey-beard loon’ !”(a) Who are the two speakers in the above lines ?(b) Why does one person use his skinny hand to hold the other person ?(c) Explain the meaning of ‘grey-beard loon’. (d) What does the word ‘quoth’ mean ?

Answer»

(a) The two speakers are the Ancient Mariner and the Wedding Guest.

(b) The Mariner did not want the Wedding Guest to leave.

(c) The Mariner is very old and looks and behaves like a crazy person.

(d) Said.

Discussion

26.	Values of two types of radius of sodium are 186 and 102 pm. Which value indicates metallic and which indicates ionic radius of sodium?
Answer» 186 pm represents metallic radius, 102 pm represents ionic radius. Reason: Ionic radius is smaller due to removal of an electron, cation is formed which has smaller radius than its parent atom.

26.

Values of two types of radius of sodium are 186 and 102 pm. Which value indicates metallic and which indicates ionic radius of sodium?

Answer»

186 pm represents metallic radius, 102 pm represents ionic radius.

Reason: Ionic radius is smaller due to removal of an electron, cation is formed which has smaller radius than its parent atom.

Discussion

27.	Successive ionization enthalpies.
Answer» IE₃ > IE₂ > IE₁ After the removal of one electron from neutral gaseous atom, the electrostatic attraction between the positively charged ion formed and the electrons increases

27.

Successive ionization enthalpies.

Answer»

IE₃ > IE₂ > IE₁

After the removal of one electron from neutral gaseous atom, the electrostatic attraction between the positively charged ion formed and the electrons increases

Discussion

28.	The ionic radii of isoelectronic species are found to be 171 pm, 136 pm & 140 pm respectively. The isoelectronic species are _____ (a) N3– , O2– , F– (b) F– , O2– , N3– (c) O2– , N3– , F– (d) N3– , F– , O2-
Answer» The isoelectronic species are N^3– , F^– , O^2–.

Discussion

29.	Assertion reason type for question select the correct choice from the following.(a) Statement 1 is true, statement 2 is true & is correct explanation for statement 1 (b) Statement 1 is true, statement 2 is true but is not correct explanation for statement 1 (c) Statement 1 is true, statement 2 is false (d) Statement 1 is false, statement 2 is true1. The size of X+ ,X & O– are identical 2. The removal of electron decreases the size while addition of e– increases the size.This is primarily due to decreases increases in electronic repulsion
Answer» (d) Statement 1 is false, statement 2 is true

Discussion

30.	Variation of first ionization enthalpies with Z = 1 to 60.Study the figure given above and answer the following: (a) Compounds of Xe are known but other noble gases do not form compounds (b) Giving reason arrange alkali metals in increasing order of first ionization enthalpies(c) Estimate the first ionization enthalpy values of Mg and Al.
Answer» (a) Ionisation energy of Xe is minimum, hence electron can be taken out from it stable noble gas configuration allowing it to make some compounds, (b) Li > Na > K > Rb > Cs. Ionisation energy decreases as size increases. As size increases, outermost elements are away from nuclear pull, so electron can be easily removed. (c) Mg = 700 kJ/mol. Al = 600 kJ/mol.

30.

Variation of first ionization enthalpies with Z = 1 to 60.Study the figure given above and answer the following: (a) Compounds of Xe are known but other noble gases do not form compounds (b) Giving reason arrange alkali metals in increasing order of first ionization enthalpies(c) Estimate the first ionization enthalpy values of Mg and Al.

Answer»

(a) Ionisation energy of Xe is minimum, hence electron can be taken out from it stable noble gas configuration allowing it to make some compounds,

(b) Li > Na > K > Rb > Cs. Ionisation energy decreases as size increases. As size increases, outermost elements are away from nuclear pull, so electron can be easily removed.

(c) Mg = 700 kJ/mol. Al = 600 kJ/mol.

Discussion

31.	Why do Na and K have similar properties?
Answer» Na and K have similar physical and chemical properties because they have same number of valence electrons.

Discussion

32.	The size of Mo is very similar to W due to_______ (a) Shielding effect (b) Actinide contraction (c) Poor Shielding by 4f electrons (d) Poor shielding by 4d electrons
Answer» The size of Mo is very similar to W due to Poor Shielding by 4f electrons

Discussion

33.	Variation of atomic radius.
Answer» Along a period – size decreases from left to right due to increase in effective nuclear charge. Size of inert gases are larger than halogens. In inert gases all orbitals are completely filled, inter electronic repulsions are maximum. Measured in terms of Vanderwaals radius Down the group – size increases due to addition of a new energy shell at each succeeding element. Ionic radius – effective distance from the centre of the nucleus of the ion upto which it exerts its influence on its electronic cloud. Radius of cation is always smaller than parent atom – size of Mg²⁺ is smaller than Mg due to increase in effective nuclear charge. Radius of anion is always larger than parent atom – size of Cl is larger than Cl due to decrease in effective nuclear charge. Variation of ionic radius among isoelectronic species Al³⁺ < Mg²⁺ < Na⁺ < F < O^2- < N^3- As the effective nuclear charge increases, size decreases

33.

Variation of atomic radius.

Answer»

Along a period – size decreases from left to right due to increase in effective nuclear charge.

Size of inert gases are larger than halogens. In inert gases all orbitals are completely filled, inter electronic repulsions are maximum. Measured in terms of Vanderwaals radius

Down the group – size increases due to addition of a new energy shell at each succeeding element.

Ionic radius – effective distance from the centre of the nucleus of the ion upto which it exerts its influence on its electronic cloud.

Radius of cation is always smaller than parent atom – size of Mg²⁺ is smaller than Mg due to increase in effective nuclear charge.

Radius of anion is always larger than parent atom – size of Cl is larger than Cl due to decrease in effective nuclear charge.

Variation of ionic radius among isoelectronic species

Al³⁺ < Mg²⁺ < Na⁺ < F < O^2- < N^3-

As the effective nuclear charge increases, size decreases

Discussion

34.	Why do elements in the same group have similar physical and chemical properties?
Answer» Elements in the same group have similar physical and chemical properties because they have same number of valence electrons.

Discussion

35.	Types of atomic radius.
Answer» 1. Covalent radius – One half of the distance between the nuclei of two covalently bonded atoms of same element in a molecule (used for non metals). 2. Van der waals radius – One half of the distance between nuclei of two identical atoms. 3. Metallic radius – One half of the internuclear distance between the two adjacent metal ions in the metallic lattice. Van der waals radius > metallic radius > covalent radius The size of the cations or anions having the same charge increases with atomic number. The 3+ cations of lanthanoides (Z = 58 to Z = 71) however, show a steady decrease with atomic number, due to inefficient shielding by the f subshells (lanthanoid contraction).

35.

Types of atomic radius.

Answer»

1. Covalent radius – One half of the distance between the nuclei of two covalently bonded atoms of same element in a molecule (used for non metals).

2. Van der waals radius – One half of the distance between nuclei of two identical atoms.

3. Metallic radius – One half of the internuclear distance between the two adjacent metal ions in the metallic lattice.

Van der waals radius > metallic radius > covalent radius

The size of the cations or anions having the same charge increases with atomic number. The 3+ cations of lanthanoides (Z = 58 to Z = 71) however, show a steady decrease with atomic number, due to inefficient shielding by the f subshells (lanthanoid contraction).

Discussion

36.	Among the elements, Li, K, Ca, S and Kr, which one is expected to have the lowest first ionization enthalpy and which one has the highest first ionization enthalpy?
Answer» K has lowest first ionization enthalpy whereas Kr has highest first ionization enthalpy.

Discussion

37.	Among the elements Li, K, Ca, S and Kr, which one is expected to have the lowest first ionization enthalpy?
Answer» K has the lowest first ionization energy. Kr has the highest first ionization energy.

37.

Among the elements Li, K, Ca, S and Kr, which one is expected to have the lowest first ionization enthalpy?

Answer»

K has the lowest first ionization energy.

Kr has the highest first ionization energy.

Discussion

38.	Among C, N, B and O which element has the highest ionization potential and which element has the lowest ionization potential. Give reason.
Answer» Element having highest ionization potential is N. Due to extra stability of half filled 2p orbital. Element having lowest ionization potential is B. Due to shielding effect of completely filled 2s orbital.

Discussion

39.	Atomic Radius.
Answer» Atomic Radius : The size of atoms may be calculated by determining the internuclear distances between two atoms and this depends on their state of bonding.

Discussion

40.	Among the elements of the third period of Na to Ar pick out the element(i) with the highest first ionization energy(ii) with the largest atomic radius(iii) that is the most reactive non-metal(iv) that is the most reactive metal.
Answer» (i) Argon (ii) Na (iii) Chlorine (iv) Sodium

40.

Among the elements of the third period of Na to Ar pick out the element(i) with the highest first ionization energy(ii) with the largest atomic radius(iii) that is the most reactive non-metal(iv) that is the most reactive metal.

Answer»

(i) Argon

(ii) Na

(iii) Chlorine

(iv) Sodium

Discussion

41.	The element with the highest first ionization potential is(a) boron(b) carbon(c) nitrogen(d) oxygen
Answer» Correct option is (c) nitrogen

Discussion

42.	Prediction of Period, Group and Block of element.
Answer» 1. Period = Principal quantum number of valence shell 2. Block = Orbital in which last electron enters 3. Group Block group no. s number of valence e^-1 s p 12 + number of valence e^- s d number of e^-1 s in (n-1) d + electron in ns orbitals

42.

Prediction of Period, Group and Block of element.

Answer»

1. Period = Principal quantum number of valence shell

2. Block = Orbital in which last electron enters

3. Group

Block group no.

s number of valence e^-1 s

p 12 + number of valence e^- s

d number of e^-1 s in (n-1) d + electron in ns orbitals

Discussion

43.	Among the elements of the third period Na to Ar pick out the element: (i) with highest first ionization enthalpy, (ii) with largest atomic radius, (iii) that is most reactive non-metal, (iv) that is most reactive metal.
Answer» (i) Ar, (ii) Na, (iii) Cl, (iv) Na

43.

Among the elements of the third period Na to Ar pick out the element: (i) with highest first ionization enthalpy, (ii) with largest atomic radius, (iii) that is most reactive non-metal, (iv) that is most reactive metal.

Answer»

(i) Ar,

(ii) Na,

(iii) Cl,

(iv) Na

Discussion

44.	Which element do you think would have been named by (i) Lawrence Berkeley Laboratory?(ii) Seaborg's group?
Answer» (i) Rutherfordium (Rf). (ii) Unnilhexium (Seaborgium).

44.

Which element do you think would have been named by (i) Lawrence Berkeley Laboratory?(ii) Seaborg's group?

Answer»

(i) Rutherfordium (Rf).

(ii) Unnilhexium (Seaborgium).

Discussion

45.	The first ionization potential in electron volts of nitrogen and oxygen atoms are respectively given by(a) 14.6, 13.6(b) 13.6, 14.6(c) 13.6, 13.6(d) 14.6, 14.6
Answer» Correct option is (a) 14.6, 13.6

Discussion

46.	Name the two elements whose existence and properties were predicted by Mendeleev though they did not exist then.
Answer» Mendeleev predicted not only the existence of gallium and germanium, but also described some of their general physical properties.

Discussion

47.	How did Mendeleev arrange the elements?
Answer» Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied the same vertical column or group.

Discussion

48.	In terms of period and group where would you locate the element with z = 114?
Answer» Period = 7 and Group = 14

Discussion

49.	Describe the two merits of long form periodic table over the Mendeleev‘s periodic table?
Answer» 1. It removed the anomalies about the position of isotopes which existed in the Mendeleev‘s table. 2. It relates the position of an element in the periodic table with its electronic configuration.

49.

Describe the two merits of long form periodic table over the Mendeleev‘s periodic table?

Answer»

1. It removed the anomalies about the position of isotopes which existed in the Mendeleev‘s table.

2. It relates the position of an element in the periodic table with its electronic configuration.

Discussion

50.	Write the atomic number of the element present in the third period and seventeenth group of the periodic table.
Answer» Atomic number = 17

Discussion

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Among the elements of the third period of Na to Ar pick out the element(i) with the highest first ionization energy(ii) with the largest atomic radius(iii) that is the most reactive non-metal(iv) that is the most reactive metal.

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Among the elements of the third period Na to Ar pick out the element: (i) with highest first ionization enthalpy, (ii) with largest atomic radius, (iii) that is most reactive non-metal, (iv) that is most reactive metal.

Which element do you think would have been named by (i) Lawrence Berkeley Laboratory?(ii) Seaborg's group?

The first ionization potential in electron volts of nitrogen and oxygen atoms are respectively given by(a) 14.6, 13.6(b) 13.6, 14.6(c) 13.6, 13.6(d) 14.6, 14.6

Name the two elements whose existence and properties were predicted by Mendeleev though they did not exist then.

How did Mendeleev arrange the elements?

In terms of period and group where would you locate the element with z = 114?

Describe the two merits of long form periodic table over the Mendeleev‘s periodic table?

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

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