What electron could have quantum numbers n=4 l=2 ml= -2 ms= 1/2

4d¹ electron has quantum numbers

n=4; l=2; ml= -2; ms= 1/2

Explanation:

There are 4 quantum numbers, namely

the principal quantum number (n)

the orbital angular momentum quantum number (l)

the magnetic quantum number (ml)

the electron spin quantum number (ms)

The principal quantum number describes the orbit or shell of the electron

here n = 4 ⇒ electron is in 4th shell

the orbital angular momentum quantum number describes the shape of orbital the electron is present in.

l= 0 ⇒ s-orbital

l= 1 ⇒ p-orbital

l= 2 ⇒ d-orbital

l= 3 ⇒ f-orbital

In our case l= 2 ⇒ p-orbital

ml specifies in which orbital electron is present of given shape

ml has 2l+1 values,which range from -1 to +l

here l = 2 ⇒ ml has 2(2)+1 = 5 values (-2 to +2)

so electron is present in one of the five d-orbitals

ms represents the spin of electron (+1/2 or -1/2)

If  +1/2 represents clockwise then -1/2 represents anti-clockwise and vice-versa.

⇒  4d¹ electron has quantum numbers

n=4; l=2; ml= -2; ms= 1/2.