Which of the subshell designations are possible and which are impossible? 1) 2p 2) 1f 3) 3s 4) 1d 5) 1p

The sub shell designations 2p, 3s are possible while the sub shell designations like 1f, 1d and 1p are not possible.

Options 1 and 3 are possible but 2,3,5 are impossible

Explanation:

The sub shell designations are represented as nL, where n is the principle quantum number and l is the azimuthal quantum number of every shell. It is known that if n is the principle quantum number of a shell, then number of electrons can occupy that particular shell.

Also, the azimuthal quantum number L has a limitation that it can only be in the range of 0 to (n-1) values [i.e. (0< L < (n-1))]. Each values of L denotes subshell and they can be represented as alphabets as s, p, d, f, g, h.

So, in this case, the option 2p represents the n = 2 and L=1 which matches the limitations of azimuthal quantum number i.e. (0< L < (n-1)) . Similarly, the option 3s consists of n = 3 and L = 0 which matches the limitations of L i.e. (0< L < (n-1)). So, the subshells 2p and 3s are possible.

But the remaining options 1f, 1d and 1p are not possible because it fails the limitations criteria of L i.e. (0< L < (n-1)). In 1f, n = 1 and L = 3, so L > n which is not at all possible according to quantum levels. Similarly for 1d, n = 1 and L = 2 and 1p, n = 1 and L = 1, both of these hinders the limitations condition of azimuthal quantum number.

the answer is b i think