Select the correct statements:

(1) Ce=4f15d16s2,Ce+3=4f15d06s0   (2) The valence shell configuration of Ln is the same since e-'s enters into the inner 4f subshell. Moreover, due to Ln contraction, the change in the size of Ln is very small. Therefore, their chemical properties are similar (3) Gd(Z=64):4f75d16s2,Gd3+=4f7Lu(Z=71):4f145d16s2,Lu+3=4f14Due to half filled and full filled stable configuration, they are stable (4) La(Z=57):5d16s2,La3+=5d06s0To obtain +4 O.S. state, the stable configuration is to be disturbed which is not possible. Henc La+4 does not exist.