What is the electron configuration of Cd2+?

1 Answer
Nov 12, 2015

[Kr]4d10

Explanation:

Your starting point here will be the electron configuration of a neutral cadmium atom.

Cadmium, Cd, is located in period 5, group 12 of the periodic table and has an atomic number equal to 48. This means that a neutral cadmium atom will have a total of 48 electrons surrounding its nucleus.

This also tells you that the Cd2+ cation, which has two electrons less than the neutral atom, will have a total of 46 electrons.

So, the electron configuration of a neutral cadmium atom looks like this

Cd: 1s22s22p63s23p64s24p64d105s2

Alternatively, you can use the noble gas shorthand notation to write cadmium's electron configuration based on that of krypton, the noble gas that comes before cadmium in the periodic table

Cd: [Kr]4d105s2

Now, the Cd2+ cation is formed when cadmium loses the electrons that are highest in energy. As you can see in the electron configuration, the two electrons that occupy the 5s-orbital match this profile.

Therefore, the electron configuration of the Cd2+ cation will be

Cd2+:[Kr]4d10