Answer to Question #175587 in General Chemistry for Dawson

Question

The partial (valence-level) orbital diagram for a 3+ ion is shown below.

__ 4s (no arrows) __ __ __ __ __ 3d (two arrows in the first box, up and down) (One up arrows in the rest of the boxes, 6 arrows total)

Write the symbol of the element from which this ion is derived.

Write the formula of the oxide this ion forms.

The answer is not Fe or Cr

Answer 1

Q175587

The partial (valence-level) orbital diagram for a 3+ ion is shown below.

__ 4s (no arrows) __ __ __ __ __ 3d (two arrows in the first box, up and down) (One up arrows in the rest of the boxes, 6 arrows total)

Write the symbol of the element from which this ion is derived.

Write the formula of the oxide this ion forms.

The answer is not Fe or Cr.

Solution:

Let us first draw the box diagram of the ion with the +3 charge.

The charge on the ion is 3+. This means that it was formed by the loss of 3 electrons.

We will fill the 3 electrons again and compare the electronic configuration with the elements in the periodic table.

First, completely fill 4s and then plug the remaining electron/s in 3d.

After filling 3 electrons, we have

Now check which element has an outer electronic configuration, 4s² 3d⁷.

The electronic configuration of cobalt is

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷

We can see that the outer electronic configuration of cobalt is 4s² 3d⁷.

So the element is Cobalt.

Write the symbol of the element from which this ion is derived.

the element is Cobalt.

The symbol of the element is Co.

Write the formula of the oxide this ion forms.

The charge on the ion is +3. We now know that the element is Co.

So the ion would be Co⁺³.

Co⁺³ and O^2- will form Co₂O₃ oxide.

Hence the formula of the oxide formed by the ion is Co₂O₃.

Hence the element is Cobalt, and the symbol of the element is Co.

Cobalt will form the Co⁺³ ion after the loss of 3 electrons.

So the ion was Co⁺³.

The formula of oxide formed by Co⁺³ is Co₂O₃.