Question

The element with atomic number 15 belongs to _____ group of the periodic table.

Answer 1

The atomic number is the number of electrons in an atom. Every element is arranged in the periodic table based on its atomic number. The element with the atomic number 15 is Phosphorus (P).

Step 1: Write the electronic configuration of the element with the atomic number 15.

P (15) = [Ne] $3{\mathrm{s}}^{2}3{\mathrm{p}}^3$

Step 2: Find the block it belongs to.

Phosphorus has five valence electrons. As the valence electron enters the p-block, Phosphorus is situated in the p-block.

Step 3: Find the group number.

For p-block elements:

Group no. = No. of valence electrons + 10

So, the group no. for Phosphorus is 5 + 10 = 15.

Thus, the element with the atomic number 15 belongs to the 15^th group of the periodic table.