What is the difference between valence electron and valency of an element discuss with an example

What is the difference between valence electron and valency of an elem

1.	What is the difference between valence electron and valency of an element discuss with an example
Answer» Valency is the electron that the atom or molecule requires to accept or donate to other atom .But valence electrons are the number of electron in the outermost shell.For example Na=(2,8,1) So Valence electron is 1 so Na will donate its 1 e- to complete its octet therefore its valency is 1 whereas S=(2,8,6) here valence electrons are 6 but it needs 2 more to make it 8 and complete octet therefore valency is 2 So valence e-= No.of e- in last shell and Valency = No. Of e- donated or accepted to complete its octet.HOPE IT HELPS:-) Take an element say chlorine atomic no. is 17, and EC will be 2,8,7, here 7 is valence electrons (electrons in the last shell) and 8-7=1 is the valency( electron needed to complete the octet) hope it helps u