Number of unpaired electron are given by

Magnetic moment = √n(n+2)

Where n is the No. of unpaired electrons

Or 1.73 = √n(n+2)

1.73×1.73=n^{2}+2n

∴ n = 1

Vanadium atom must have one unpaired electron and thus its configuration is

_{23}V^{4+}:1s^{2},2s^{2}2p^{6},3s^{2}3p^{6}3d^{1}