Write the number of periods and groups in the Modern Periodic Table. How does the metallic character of elements vary on moving
(i) from left to right in a period, and
(ii) down a group? Give reason to justify your answer.
(i) In the modern periodic table, there are 18 vertical columns known as groups and 7 horizontal rows knows as periods.
(ii) Metallic character: It is a tendency of an atom to loose electrons.
Across the Period: Metallic character decreases.
(iii) Down the group: Metallic character increases.
Reason: Across the period, the effective nuclear charge increases due to which atomic radius decreases. Which favours the increase in electronegativity and thus, tendency to loose electron is low and thus, metallic property decreases along the period.
But when we move down the group, the number of shells increases and thus, atomic size also increases and thus, electronegativity decreases and hence, metallic character increases.