Electron Cloud is divided into energy levels.      Analogy:  Rows of seats in the stadium

The first energy level is closest to the nucleus.  It must contain 2 electrons before the second energy level can hold electrons.

The other energy levels must contain 8 electrons before you can start filling the next energy level.

Use the model on the right to answer the following questions. 

Calcium has a total of 20 electrons. 

• How many electrons are in the 1^st energy level?

• How many electrons are in the 2^nd energy level?

• How many electrons are in the 3^rd energy level?

• How many electrons are in the 4^th energy level?

• Add up all of the electrons in each energy level. 

• What is the total number of electrons in the entire cloud?

APPLY WHAT YOU KNOW: 
Complete the table in your notes by writing the number of electrons that would be present in each energy level of an atom of each of these elements. Remember, you must start filling energy levels closest to the nucleus first and you can’t fill the next energy level until the one before it is filled. 

BRING YOUR WORK TO ME SO I CAN CHECK YOUR UNDERSTANDING BEFORE YOU MOVE ON!

Now complete the take away ideas box before you move on to Part 9.