How many groups and periods are there in the modern periodic table? How do the atomic size and metallic character of elements vary as we move:
(a) Down a group and
(b) From left to right in a period
The modern periodic table consists of 18 groups and 7 periods.
i) Down the group, the atomic size and metallic character of elements increase.
ii) On moving from left to right in a period, the atomic size and metallic character of elements decreases.