Question

Select the false statement below concerning period 4 transition elements. A. The nickel atom has 18 inner/core electrons. B. Both the chromium atom and the manganese atom have half-filled d subshells. C. The vanadium atom has fewer unpaired electrons than the nickel atom. D. The titanium atom has more unpaired electrons than the zinc atom. E. The iron atom has 8 valence electrons.

Answer 1

Explanation:

Atomic number of nickel is 28 and its electronic distribution is 2, 8, 8, 2, 8. Therefore, in the inner/core electrons there are 18 electrons.

Atomic number of chromium is 24 and its electronic configuration is $[Ar]4s^{1}3d^{5}$. Whereas atomic number of manganese is 25 and its electronic configuration is $[Ar]4s^{2}3d^{5}$.

Hence, the statement both chromium atom and the manganese atom have half-filled d sub-shells, is true.

Atomic number of Vanadium is 23 and its electronic configuration is $[Ar]4s^{2}3d^{3}$. Atomic number of nickel is 28 and its electronic configuration is $[Ar]4s^{2}3d^{8}$.

So, there are three unpaired electrons in a Vanadium atom and in nickel atom there are 2 unpaired electrons.

Hence, the statement vanadium atom has fewer unpaired electrons than the nickel atom, is false.

Atomic number of titanium is 22 and its electronic configuration is $[Ar]4s^{2}3d^{2}$. Atomic number of zinc is 30 and its electronic configuration is $[Ar]4s^{2}3d^{10}$.

There are no unpaired electrons in a zinc atom. Hence, the statement titanium atom has more unpaired electrons than the zinc atom, is true.

Atomic number of iron is 26 and its electronic configuration is $[Ar]4s^{2}3d^{6}$. Since, 4s is the outermost shell so, in iron atom there are 2 valence electrons.

Hence, the statement iron atom has 8 valence electrons, is not true.

Thus, we can conclude that false statements below concerning period 4 transition elements are as follows.

• The vanadium atom has fewer unpaired electrons than the nickel atom.

• The iron atom has 8 valence electrons.