# Question #0137b

May 9, 2017

Atomic number 15 $1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{3}$

#### Explanation:

Phosphorus number 15 is a very unstable element. It has five valance electrons. 10 electrons are in the filled second shell leaving five valance electrons. the $3 {s}^{2} 3 {p}^{3}$

Phosphorus can lose electrons giving a charge of +3 and +5.
Phosphorus can also gain electrons achieving a charge of -3

So the electron configuration is

$1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{3}$