Question

write the electron configuration of an atom of the element highlighted in this outline of the periodic table:
hint: you do not need to know the name or symbol of the highlighted element!

Explanation:

Step1: Determine the number of electrons

The element is in the fourth period. The noble gas core for the fourth period is Ar (which has 18 electrons). The element is in the first row of the transition - metal block (d - block) in the fourth period. The general electron - configuration pattern for elements in the fourth period is \([\text{Ar}]4s^{2}3d^{x}\). Since it is the first element in the d - block of the fourth period, \(x = 1\).

Step2: Write the electron configuration

The electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{1}\) which can be written in noble - gas core form as \([\text{Ar}]4s^{2}3d^{1}\)

Answer:

\([\text{Ar}]4s^{2}3d^{1}\) or \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{1}\)