How many electrons in an atom can have the quantum numbers n = 4, l = 0, ml = 0, ms = + 1/2?

1

2

3

6

The answer is 1.

Explanation:

Four quantum numbers are used to describe an electron:

n is the Principal quantum number which deals with its energy state,

l is the Azimuthal quantum number which describes its angular momentum,

m or ml is the Magnetic quantum number which relates to magnetic,

s or ms is the Spin quantum number which covers spin.

Each electron is unique in its set of quantum numbers. So there can only be one.

1

Explanation:

Only one electron can have the given set of quantum numbers. This is because no two electron in an atom can have the same set of quantum numbers.