Explanation:
Scandium has atomic number of 21. This means that in it's neutral state its going to have 21 electrons.
a) The full electronic configuration is given as;
1s2 2s2 2p6 3s2 3p6 3d1 4s2
The final electron is placed in the d orbital. The shell is 3d
(b) When scandium has a charge if +1, it has lost an electron. The total number of electrons would now be 21-1 = 20
The electronic configuration would be given as;
1s2 2s2 2p6 3s2 3p6 4s2
The electron in the 3d orbital would be removed.
