Answer: n = 1 can hold a maximum of 2 electrons
n = 2 , maximum 8 electrons
n = 3, maximum 18 electrons
As per the principles of quantum mechanics, the number of electrons that can be added to a given energy level is deduced based on the three quantum numbers: n, l , m(l) and m(s)
'n' is the principal quantum number which defines the energy level. It can take on integer values: 0,1,2,3...
'l' is the angular momentum quantum number which defines the shape of the orbital that an electron occupies
l = 0,1,2...(n-1)
where: l = 0 corresponds to s-orbital
l = 1 corresponds to p-orbital
l = 2, corresponds to d-orbital
'm(l)' is the magnetic moment quantum number which defines the orientation of an orbital in space.
m(l) = -l, 0, +l
'm(s)' is the spin quantum number which defines the orientation of an electron is an orbital m(s) = +1/2 or -1/2
An s, p or d-orbital can accommodate a maximum of 2, 6 and 10 electrons respectively For energy level with n= 1
l = 0, i.e. s-orbital or 1s.
Therefore, the maximum number of electrons for a 1s orbital would be 2 resulting in an electron configuration of 1s²
For energy level with n= 2
l = 0, 1 i.e. s and p-orbitals
The maximum number of electrons would be
Electron configuration: 2s²2p⁶
For energy level with n= 3
l = 0, 1, 2 i.e. s, p and d-orbitals
The maximum number of electrons would be
Electron configuration: 3s²3p⁶3d¹⁰
