How many electrons are present in a 4p orbital?

1 Answer

Two electrons.

Explanation:

A #4p# orbital, which is part of the #p# subshell located on the fourth energy level, can hold a maximum of two electrons.

In fact, any orbital, regardless of its energy level, subshell, and orientation, can hold a maximum of two electrons, one having spin-up and one having spin-down.

This is the case because according to the Pauli Exclusion Principle, two electrons located in an atom cannot share a complete set of four quantum numbers.

To the level of an orbital, this comes down to one of the two electrons that share an orbital having spin-up, which is given by the spin quantum number #m_s = +1/2#, and the other having spin-down, which is given by #m_s = -1/2#.

Now, the #4p# subshell contains a total of three #4p# orbitals, #4p_x#, #4p_y#, and #4p_z#.

http://www.geo.arizona.edu/xtal/geos306/fall02-2.htm

Since each of those #p# orbitals can hold a maximum of two electrons, the #p# subshell can hold a maximum of

#3 color(red)(cancel(color(black)("p orbitals"))) * "2 e"^(-)/(1color(red)(cancel(color(black)("p orbital")))) = "6 e"^(-)#

Therefore, you can say that a #4p# orbital can hold a maximum of two electrons and the #4p# subshell can hold a maximum of six electrons.