Question

Which of the following quantum number combinations is not allowed in an atom?

Answer 1

The fourth combination is not allowed.


The third quantum number, i.e. m subscript l, only may an integer number from -l to + l. Given that l = 0, the only allowed m subscript l is 0.

Answer 2

The answer is n = 1, l = 0, m subscript l = 1

The 4 quantum numbers of the electronic configuration

n: main quantum number. It defines the layer.

n = 1 at layer K

n = 2 at layer L

n = 3 at layer M

And so on…

The energy of the electron is a function of n.

l: secondary or azimuth quantum number

it is an integer that varies from 0 to n-1. It defines the sub-layers s, p, d, f

l = 0 under layer s

l = 1 under layer  p

l = 2 under layer d

l = 3 under layer f

It defines the shape and symmetry of the orbitals (orbital s, p, d etc ...)

Example n = 2 to l = 0 or l = 1 from which 2 sublayers 1s and 2p

m: magnetic quantum number

It takes values ​​between -l and l (including the values ​​of -l and l). At a value of m, correspond to 2l + 1 value of m. It determines the orbital orientation in space (see the shape of the orbitals.

s: quantum number of spin

The quantum number of spin is defined as the kinetic moment (or angular momentum) of the electron. s = -1 / 2 or ½ (2 directions of rotation of the electron on itself)