Question

As the first five elements in Group 15 are

considered in order of increasing atomic number,
first ionization energy
(1) decreases
(2) increases
(3) decreases, then increases
(4) increases, then decreases

Answer 1

Answer: The first ionization energy for the first five elements of Group 15 decreases.

Step-by-step explanation:

Ionization energy is defined as the energy required to remove an electron from the outermost shell of an isolated gaseous atom. It is represented as
`E_i`

`X(g)\rightarrow X^+(g)+1e^-;E_i`

Ionization energy decreases as we move down the group. This happens because the number of shells increases as we move down the group. The electrons are added in the new shell around the nucleus.

This results in the shielding of outermost electrons more from the inner ones, which decreases the attraction between the outermost electrons and the nucleus. Hence, the removal of electron from the outermost shell becomes easy and requires less energy.

Hence, the first ionization energy for the first five elements of Group 15 decreases.

Answer 2

The correct answer is option 1. The first ionization energy, in group 15 elements in increasing atomic number, decreases. Ionization energy is the amount of energy requires to detach one electron from the atom. In the periodic table, the ionization energy decreases as one goes down.