Why the third period of Modern periodic table contains `8` elements and not `18`?

Modern periodic table contains _____ groups.

Define a period of the modern periodic table of elements.

The first period of the modern periodic table has __________ elements .

Na and S are present in the third period of modern periodic table which is more metallic and why?

On the basis of quantum numbers, justify that the fourth period of the Modern periodic table should have 18 elements.

On the basis of quantum numbers, justify that the fourth period of the Modern periodic table should have 18 elements.

In the Modern Periodic Table, which period contains 32 elements?

In the modern periodic table, elements are arranged in