Electronic configuration of Ti = [Ar]4s^{2}3d^{2}

Ti^{3+ }which means it loses three electrons from outermost orbit therefore the configuration becomes

Ti^{3}^{+} = [Ar]3d^{1} ------ which means outermost shell has 1 electron

Spin only formula=

where n =1 for Ti^{3+}

μ=√3