How many groups and periods are there in the Modern Periodic Table?

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

Answer:

There are 18 groups and 7 periods in the Modern Periodic Table.

  • Atomic size increases
  • Metallic character increases
  • Atomic size decreases
  • Metallic character decreases