# Strontium Bohr model

In the strontium Bohr model, the nucleus comprises 38 protons and 50 neutrons. Surrounding this nucleus are five electron shells, hosting a total of 38 electrons.

To draw the strontium Bohr model, represent the 38 protons, 50 neutrons, and 38 electrons. Start by sketching the nucleus, and then illustrate the five electron shells. The first two shells should contain 2 and 8 electrons, respectively, while the third shell holds 18 electrons. The fourth and fifth shells accommodate 8 and 2 electrons, respectively.

Contents

## Steps

### Write protons, neutrons, and electrons of strontium atom

Strontium has 38 protons, 50 neutrons, and 38 electrons.

### Draw nucleus of strontium atom

The nucleus of a strontium atom contains 38 protons and 50 neutrons. So draw the nucleus of strontium atom as follows:

Now in the next step, draw the 1st electron shell and start marking electrons.

### Draw 1st electron shell

Remember that we have a total of 38 electrons.

The 1st electron shell (containing s subshell) can hold up to a maximum of 2 electrons. So draw the 1st electron shell as follows:

In the above image, 1 represents the 1st electron shell that contains 1s subshell. And the green color represents the number of electrons in that subshell. This means that the 1st electron shell has a total of 2 electrons.

Since we have already used 2 electrons in the 1st electron shell, now we have 38 – 2 = 36 electrons left. So in the next step, we have to draw the 2nd electron shell.

### Draw 2nd electron shell

The 2nd electron shell (containing s subshell and p subshell) can hold up to a maximum of 8 electrons. So draw the 2nd electron shell as follows:

In the above image, 2 represents the 2nd electron shell that contains 2s and 2p subshells. And the green and orange color represents the number of electrons in that subshell. This means that the 2nd electron shell has a total of 8 electrons.

Now we have already used 10 electrons in 1st and 2nd electron shells, so we have 38 – 10 = 28 electrons left. So in the next step, we have to draw the 3rd electron shell.

### Draw 3rd electron shell

The 3rd electron shell (containing s subshell, p subshell, and d subshell) can hold up to a maximum of 18 electrons. So draw the 3rd electron shell as follows:

In the above image, 3 represents the 3rd electron shell that contains 3s, 3p, and 3d subshells. And the green, orange, and pink color represents the number of electrons in that subshell. This means that the 3rd electron shell has a total of 18 electrons.

Now we have already used 28 electrons in 1st, 2nd, and 3rd electron shells, so we have 38 – 28 = 10 electrons left. So in the next step, we have to draw the 4th electron shell.

### Draw 4th electron shell

The 4th electron shell (containing s subshell, p subshell, d subshell, and f subshell) can hold up to a maximum of 32 electrons. So draw the 4th electron shell as follows:

In the above image, 4 represents the 4th electron shell that contains 4s and 4p subshells. And the green and orange color represents the number of electrons in that subshell. This means that the 4th electron shell has a total of 8 electrons.

The 4th electron shell contains only 4s and 4p subshells, and not 4d and 4f subshells. This is because according to the aufbau principle, the 5s subshell is filled first and then 4d, 5p, 6s… and so on.

Now we have already used 36 electrons in 1st, 2nd, 3rd, and 4th electron shells, so we have 38 – 36 = 2 electrons left. So in the next step, we have to draw the 5th electron shell.

### Draw 5th electron shell

The 5th electron shell can hold up to a maximum of 50 electrons. So draw the 5th electron shell as follows:

In the above image, 5 represents the 5th electron shell that contains 5s subshell. And the green color represents the number of electrons in that subshell. This means that the 5th electron shell has a total of 2 electrons.

That’s it! This is the final Bohr model of strontium atom as we have used all 38 electrons: 2 electrons in the 1st electron shell, 8 electrons in the 2nd electron shell, 18 electrons in the 3rd electron shell, 8 electrons in the 4th electron shell, and 2 electrons in the 5th electron shell.

Next: Cesium Bohr model