Question

The electron configuration of an element is 1s22s22p¹. How many valence electrons does the element have

a) 1
b) 2
c)3
d)4

Answer 1

`\huge\boxed{\sf 3 \ electrons}`

Step-by-step explanation:

Electronic configuration:

`1s^22s^22p^1`

The outermost/valence shell is the second one, seeing from the electronic configuration.

Valence electrons:

= 2 + 1 = 3 (electrons are raised to the power in the electronic configuration)

Since, the valence shell here is 2, the electrons of second shell will be counted as valence electrons.

`\rule[225]{225}{2}`