Question

The triply ionised beryllium (Be⁺⁺⁺) has the same electron orbital radius as that of the ground state of the hydrogen atom. The energy state (n) of triply ionised beryllium is ______.

(Z for beryllium = 4)

Options

• 3

• 1

• 4

• 2

Answer 1

The triply ionised beryllium (Be⁺⁺⁺) has the same electron orbital radius as that of the ground state of the hydrogen atom. The energy state (n) of triply ionised beryllium is 2.

Explanation:

The radius of the atomic orbit is given by,

`r_n = 0.059 n^2/Z`

For Be³⁺, Z = 4

According to the question,

`r_0/Z_1^2 = r_n/Z_2^2`

⇒ `(1)^2/1 = n^2/4 ⇒ n = 2`