Mrs. Sands 8th Grade science How to Draw Lewis Structures Mrs. Sands 8th Grade science

Take out a sheet of notebook paper and set up like this…

Bohr’s Diagram Bohr’s diagram is how scientists draw atoms showing the placement of all of the electrons.

How to Draw Bohr Diagrams

Bohr Diagrams 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. Elements in the 1st period have one energy level. Elements in the 2nd period have two energy levels, and so on. www.chem4kids.com

C Bohr Diagrams Write the element symbol. Carbon is in the 2nd period, 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. Each shell has a maximum number of electrons it can hold 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. Only two electrons can fit in the 1st shell. The 2nd shell can hold up to 8 electrons. The 3rd shell can also hold 8 electrons. C

Maximum Electrons in Each Shell The further the shells are from the nucleus, the bigger he shells get. Bigger shells can fit more electrons. The 4th and 5th shell can hold 18 electrons. The 6th and 7th shell can hold 32 electrons.

Bohr Diagrams 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

Bohr Diagrams He Try the following elements on your own: H He - 2 electrons O Al Ne K He

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

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

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

Bohr Diagrams K Try the following elements on your own: H He O Al Ne K - 19 electrons K

Lewis Dot Structure

Lewis Structures Find your element on the periodic table. Determine the number of valence electrons. Valence electrons are the number of electrons in the outer shell of the electron cloud. This is how many electrons you will draw. Here’s how…

Lewis Structures Find out which group (column) your element is in. This will tell you the number of valence electrons your element has. You will only draw the valence electrons. www.chem4kids.com

Groups - Review Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electrons Group 2 = 2 electrons Each column is called a “group” 3, 4, 5, 6, 7 Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. The electrons in the outer shell are called “valence electrons” www.chem4kids.com

C Lewis Structures Write the element symbol. Carbon is in the 14th column (group), so it has 4 valence electrons. This is how 4 valence electrons look on the Lewis dot diagram. C

C Lewis Structures Check your work. Using your periodic table, check that Carbon is in the 14th column (group)). You should have 4 total electrons, or dots, drawn in for Carbon. C

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar C

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar H

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar Ca

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar Al

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar P

O Lewis Structures H Ca Al P Cl Ar Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P Cl Ar O

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P O Cl Ar Cl

Lewis Structures Here is how different Lewis dot diagrams look with a different number of valence electrons: H Ca Al P Cl Ar Ar

Why do we do these drawings? Lewis Dot structure is what scientists use to write down/draw what happens to molecules when they bond.