www.middleschoolscience.com 2008 Making Your Own Periodic Table – Part 1 -How to Draw Bohr Diagrams of Atoms www.middleschoolscience.com 2008

Please open your textbook to pages 242-243 or take out your periodic table.

Anything in red print should be written in your notebook.

How to Draw Bohr Diagrams of Atoms Find your element on the periodic table. Determine the number of electrons – it is the same as the atomic number. This is how many electrons you will draw.

Bohr Diagrams Find out which period (row) your element is in Periods- rows on the periodic table; tells how many energy levels(shells/orbitals) your element has. Elements in the 1st period (row) have one energy level. Elements in the 2nd period (row) have two energy levels, and so on. There are 7 periods (rows) so there can be up to 7 orbitals. 1 2 3 4 5 6 7 67 www.chem4kids.com

Bohr Diagrams Write the element symbol (leave some space around it.) This represents the nucleus. Carbon is in the 2nd period (row), so it has two energy levels, or shells. Draw the shells around the nucleus. C

C Bohr Diagrams Add the electrons. Carbon has 6 electrons. The first shell can only hold 2 electrons. C

Bohr Diagrams Since you have 2 electrons already drawn, you need to add 4 more. These go in the 2nd shell. Add one at a time -starting on the right side and going counter clock-wise. C

C Bohr Diagrams Check your work. You should have 6 total electrons for Carbon. The first shell can hold only 2 electrons. The 2nd shell can hold up to 8 electrons. The 3rd shell can hold 18, but the elements in the first few periods (rows) only use 8 electrons. C

Bohr Diagrams In your notebook, try the following elements on your own: H He O Al Ne K C

H Bohr Diagrams Try the following elements on your own: H – 1 electron Al Ne K H

He Bohr Diagrams Try the following elements on your own: H He - 2 electrons O Al Ne K He Helium has two electrons. They are always shown together. It’s the only weird one.

O Bohr Diagrams Try the following elements on your own: H He O - 8 electrons Al Ne K O

Al Bohr Diagrams Try the following elements on your own: H He O Al - 13 electrons Ne K Al

Ne Bohr Diagrams Try the following elements on your own: H He O Al Ne - 10 electrons K Ne

And that is Step 1 toward making your own periodic table – How to Draw Bohr Diagrams

Now, on your Bohr diagrams worksheets, draw Bohr diagrams for the remaining elements.

Stop here.