Question

The circles, or orbits, for electrons are called energy levels. Each level can hold only a certain number of electrons. Add electrons to each level until you can’t add any more. How many electrons can each level hold?

Answer 1

Answer:

n = 1 can hold a maximum of 2 electrons

n = 2 , maximum 8 electrons

n = 3, maximum 18 electrons

Explanation:

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:

$2(s,orbital) + 6(p,orbital) = 8$

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:

$2(s,orbital) + 6(p,orbital) + 10(d,orbital)= 18$

Electron configuration: 3s²3p⁶3d¹⁰

Answer 2

It is a bit complicated because the second shell can hold only up to 8 for the elements under the periods but for the transition metals it can hold more.