What is the difference between valence electrons and valency of an element ? Discuss with an example.

The valency of an element is

What is the major difference between valence bond molecular orbital theories ?

(a) What is the usual number of valence electrons and valency of group 18 elements of the periodic table? (b)What happens to the number of valence electrons in the atoms is elements as we go down in a group of the periodic table?

The sum of number of valence electrons and valency of an element with atomic number 15 is_____.

The valence electrons of an element are respon­sible for