Question

Select the correct ground state electronic configuration

	$ Cr $	$ Eu $	$ Ti^{2+} $
(a)	$ \left[Ar\right] 3d^{5} 4s^{1} $	$ \left[Xe\right]4f^{7} 5d^{0} 6s^{2} $	$ \left[Ar\right] 3d^{2} 4s^{0} $
(b)	$ \left[Ar\right] 3d^{4} 4s^{2} $	$ \left[Xe\right]4f^{7} 5d^{0} 6s^{2} $	$ \left[Ar\right] 3d^{2} 4s^{2} $
(c)	$ \left[Ar\right] 3d^{4} 4s^{2} $	$ \left[Xe\right]4f^{6} 5d^{1} 6s^{2} $	$ \left[Ar\right] 4s^{2} 4d^{0} $
(d)	$ \left[Ar\right] 3d^{5} 4s^{1} $	$ \left[Xe\right]3f^{6} 5d^{2} 6s^{1} $	$ \left[Ar\right] 4s^{1} 3d^{1} $

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (A)

The correct electronic configuration is :
$Cr(24) = [Ar]^{18}3d^54s^1$
$Eu(63) = [Xe]^{54}4f^76s^2$
$Ti^{2+}(22) = [Ar]^{18}3d^24s^0$