Which orbital in each of the following pairs is lower in energy in a

1.	Which orbital in each of the following pairs is lower in energy in a many electron atom?(a) 2s, 2p(b) 3p, 3d(c) 3s, 4s(iv) 4d, 5f
Answer» According to Bohr's Bury rule, the orbital having lower (n + l) value has lower energy. (a) 2s, 2p For 2s orbital, (n + l) = 2 + 0 = 2 For 2p orbital, (n + l) = 2 + 1 = 3 Since, 2s-orbital has lower (n + l) value, it has lower energy than 2p-orbital. (b) 3p, 3d For 3p orbital (n + l) = 3 + 1 = 4 For 3d orbital (n + l) = 3 + 2 = 5 Since, 3p, orbital has lower (n + l) value, it has lower energy than 3d-orbital. (c) 3s, 4s For 3s orbital (n + l) = 3 + 0 = 3 For 4s orbital (n + l) = 4 + 0 = 4 Since, 3s-orbital has value (n + l) value, it has lower energy than 4s-orbital. (d) 4d, 5f For 4d orbital, (n + l) = 4 + 2 = 6 For 5f orbital, (n + l) = 5 + 3 = 8 Since, 4d-orbital has lower (n + l) value, it has lower energy than 5f-orbital.

Which orbital in each of the following pairs is lower in energy in a many electron atom?(a) 2s, 2p(b) 3p, 3d(c) 3s, 4s(iv) 4d, 5f

Answer»

According to Bohr's Bury rule, the orbital having lower (n + l) value has lower energy.

(a) 2s, 2p

For 2s orbital, (n + l) = 2 + 0 = 2

For 2p orbital, (n + l) = 2 + 1 = 3

Since, 2s-orbital has lower (n + l) value, it has lower energy than 2p-orbital.

(b) 3p, 3d

For 3p orbital (n + l) = 3 + 1 = 4

For 3d orbital (n + l) = 3 + 2 = 5

Since, 3p, orbital has lower (n + l) value, it has lower energy than 3d-orbital.

(c) 3s, 4s

For 3s orbital (n + l) = 3 + 0 = 3

For 4s orbital (n + l) = 4 + 0 = 4

Since, 3s-orbital has value (n + l) value, it has lower energy than 4s-orbital.

(d) 4d, 5f

For 4d orbital, (n + l) = 4 + 2 = 6

For 5f orbital, (n + l) = 5 + 3 = 8

Since, 4d-orbital has lower (n + l) value, it has lower energy than 5f-orbital.