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 a group.

Write the number of periods the modern periodic table has. State the c

1.	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 a group.
Answer» SOLUTION :No. of periods : 7. Valency across a PERIOD increases from 1 to 4, then decreases from 4 to ZERO. Metallic character of ELEMENTS across a period decreases. Valency remains the same down a group Atomic SIZE of elements increases down a group.