Question

How many elements are there in period 2?

Answer 1

The period in the periodic table:

1. The elements in the horizontal rows of a periodic table represent periods.
2. The 2nd-period elements are the elements in the 2nd row of the periodic table.

The number of elements in a period can be determined as:

Let 'p' be the period number, and

1. If p is even, then the number of elements: $\frac{{\left(p+2\right)}^2}{2}$
2. If p is odd, then the number of elements: $\frac{{\left(p+1\right)}^2}{2}$

Since the period number is 2, it is even.

Therefore, the number of elements in period 2 will be

$\frac{{\left(2+2\right)}^2}{2}=\frac{16}{2}=8$

Hence, there are 8 elements in period 2 of the periodic table.