Question

An element belongs to group IA and 3rd period in the periodic table. Find an atomic number of that element. Find the atomic number of elements that are placed just
A) below

B) above to the given element in the periodic table.

Answer 1

The elements of the $IA$ are hydrogen, lithium, sodium, potassium, and so on. Hence the element in the 3rd period of this group will be sodium($Na$)

The atomic number of sodium $=11$

$A)$ Element placed below $Na$ is $K$

The atomic number of potassium $=19$

$B)$ Element placed above $Na$ is $Li$

The atomic number of lithium$=3$