Electron Configuration

Here are some examples of electron configuration.

1. On the periodic table the atomic number of magnesium, Mg, is 12. There are 12 electrons in

magnesium. Using the table below we would place the electrons like this:

in 1s

in 2s

in 2p

in 3s

The electron configuration is 1s

. The small exponent indicates how many electrons are

in that level.

The orbital diagram would be ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ In each orbit one e

is up and one e

is down.

1s 2s

2. Oxygen has 8 electrons: 2e

in 1s, 2e

in 2s, and 4e

in 2p to give 1s

↑↓ ↑↓ ↑↓ ↑ ↑_

The orbital diagram would be

The 2p orbit puts three e

is up and then starts filling the remaining electron in the opposite spin

direction (down.)

0 votes

Parent category: Education