◦ NameColor Burned  1  2  3  4  5  6  Unknown #1  Unknown #2

How to draw Bohr Diagrams and Electron Dot Diagrams (sometimes called Lewis Structures)

 Pictographic representation of an Atom Shows information about the nucleus Electron energy levels Good for index cards and flash cards

Start with a rectangle about 2” x 4”

At the top write the name, Atomic number, Mass number of the element and the atomic mass Carbon Atomic # = 6 Mass # = 12 Atomic mass = amu

Draw a small circle below the text that will represent the nucleus of the atom In the circle write: the elemental symbol the number of Protons the number of Neutrons Carbon Atomic # = 6 Mass # = 12 Atomic mass = amu C 6p + 6n 0

Draw a larger circle around the nucleus circle to represent the first energy level for electrons Carbon Atomic # = 6 Mass # = 12 Atomic mass = amu Add more circles outside to include all of the energy levels you need for the atom. (Hint: In what period is the element?) Carbon is in Period two and therefore needs two energy levels C 6p + 6n 0

 Find out which period (row) your element is in.  Elements in the 1 st period have one energy level.  Elements in the 2 nd period have two energy levels, and so on.

Now add electrons, as small dots, to each energy level as allowed until you have the proper number of electrons for a neutral element. Carbon Atomic # = 6 Mass # = 12 Atomic mass = amu The number of electrons should be equal to the number of protons. Remember : Energy Level # of e C 6p + 6n 0 If you need a third level make your circles a little smaller.

You now have a complete Bohr Diagram Carbon Atomic # = 6 Mass # = 12 Atomic mass = amu C 6p + 6n 0

1) Draw a nucleus with the element symbol inside. 2) Carbon is in the 2 nd period, so it has two energy levels, or shells. 3) Draw the shells around the nucleus. C C

1) Add the electrons. 2) Carbon has 6 electrons. 3) The first shell can only hold 2 electrons. C C

1) Since you have 2 electrons already drawn, you need to add 4 more. 2) These go in the 2 nd shell. 3) Add one at a time -starting on the right side and going counter clock-wise. C C

1) Check your work. 2) You should have 6 total electrons for Carbon. 3) Only two electrons can fit in the 1 st shell. 4) The 2 nd shell can hold up to 8 electrons. 5) The 3 rd shell can hold 18, but the elements in the first few periods only use 8 electrons. C C

Try the following elements on your own: a)H b)He c)O d)Al e)Ne f)K C C

Try the following elements on your own: a)H – 1 electron b)He c)O d)Al e)Ne f)K H H

Try the following elements on your own: a)H b)He - 2 electrons c)O d)Al e)Ne f)K HeHe HeHe

Try the following elements on your own: a)H b)He c)O - 8 electrons d)Al e)Ne f)K O O

Try the following elements on your own: a)H b)He c)O d)Al - 13 electrons e)Ne f)K Al

Try the following elements on your own: a)H b)He c)O d)Al e)Ne - 10 electrons f)K NeNe NeNe

Try the following elements on your own: a)H b)He c)O d)Al e)Ne f)K - 19 electrons K K

 Also called Lewis Structures  Representation of valence electrons only  Useful only for “Representative elements”  Gives some indication of the geometry (shape) of compounds when used for bonding diagrams  Easy to draw

 To find the # of valence electrons look at the group  Group 1  Group 2  Group # = # of valence electrons

 The Elemental Symbol serves as the representation of the nucleus

 Dots are added around the nucleus to show electrons only in the outer energy level Carbon has only 4 electrons in the 2 nd energy level so we need only represent those 4 Like the Hund rule add 1 electron per side, then add more as needed.

 Lewis structures only apply to “Representative elements” (Group A elements) Only s and p sublevel electrons in the outer or highest energy level are shown. These are called valence electrons. The maximum number of electrons that can be shown are 8

 Lewis structures only apply to “Representative elements” (Group A elements) The maximum number of electrons that can be shown are 8 Only s and p sublevel electrons in the outer or highest energy level are shown. These are called valence electrons.

 Lewis structures only apply to “Representative elements” (Group A elements) The maximum number of electrons that can be shown are 8 Only s and p sublevel electrons in the outer or highest energy level are shown. These are called valence electrons.

 Lewis structures only apply to “Representative elements” (Group A elements) The maximum number of electrons that can be shown are 8 Only s and p sublevel electrons in the outer or highest energy level are shown. These are called valence electrons.

 Transition metals don’t have valence electrons. They have Oxidation Numbers We’ll Talk about Oxidation Numbers Next Week!