Write the number of periods the modern periodic table has. State the changes in valency and metallic character of elements

Write the number of periods the modern periodic table has. State the changes in valency and metallic character of elements as we move from left to right in a period. Also state the changes, if any, in the valency and atomic size of elements as we move down in a group.

The modern periodic table has seven periods.

On moving from left to right in the periodic table, the metallic character of elements decreases, while the valency first increases from 1 to 4 and then decreases to 0 (zero). On moving down the group, the atomic size of the elements increases, but the valency remains the same.