(a) What is the number of valence electrons in the atoms of first element in a period ?
(b) What is the usual number of valence electrons in the atoms of the last element in a period ?
(a) What are 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 of elements as we go down in a group of the periodic table?
What happens to number of valence electrons in atoms of elements as we go down a group of the periodic table ?