QQ: Complete the Boxes: Calcium- # protons # neutrons 24 28 # electrons 44 48 20 20 20 20 Compare these two calcium atoms. How are they alike? How are they different? What are they called?

Today’s Objective: I understand how ions create compounds.

Stable Electron Configurations When the highest energy level is filled Not likely to react 8 for many atoms

* Lost an electron or gained an electron Ion: An atom that has a positive or negative charge * Lost an electron or gained an electron

O-1 Cl- O-2 Anion: A negatively charged atom Has 1 or more extra electrons

It’s outside energy level has 8 e-

A Sulfur atom has 18 e-. S-2 A Carbon atom has 10 e-. C-4

Na+1 Ca+2 Ca+1 Cation: A positively charged atom Lost 1 or more extra electrons

They’ve lost e-

A Magnesium atom has 10 e- Mg+2 A Potassium atom has 18 e- K 1+

But are their outer electron shells filled?

Total is O charge! Na Cl +1 -1 Stable!

A Potassium atom has 18 e-. K+1 A Magnesium atom has 14 e- Mg-2

Ionic Bond: * holds anions and cations together * Electrons are transferred to another atom

Highest orbital filled = STABLE Usually 8 e-

Amount of energy needed to remove an electron Ionization Energy Amount of energy needed to remove an electron

Increases toward top right Ionization Energy Increases toward top right Most Least

Ionic Compounds Formed by ionic bonds What?