1. November 13, 2017
Journal: Draw an atom of Sodium.

2. Bonding to Make Compounds

3. Molecules
A substance made of two or more atoms
Ex: H2O, CO2

4. How do Atoms Combine?
Through valence electrons forming a bond

5. Types of Bonds
Ionic Bond
Covalent Bond
Hydrogen Bond

6. Ionic Bonds
When bonds form between atoms by either gaining or losing electrons
Results in the atom having either a positive or negative charge which is attracted to the other atom in the molecule

7. Ions When an atom has an electrical charge it is called an ion
If an atom gains an electron it has a negative charge
If an atom loses an electron it has a positive charge

8. Covalent Bonds
When bonds form between atoms by sharing valence electrons

9. Polarity
When shared electrons are attracted to one atom more strongly than another, so it has a slightly negative charge
The other atom that the electrons are less strongly attracted to has a slightly positive charge

10. Hydrogen Bond
When a hydrogen atom has a partial positive charge that attracts to the negative end of specific other molecules such as oxygen, nitrogen, and fluorine
Often observed in water
This is a relatively weak bond, but it allows water to have some special properties

11. What is special about water?
Talk to a partner and write down an answer to the question above.

12. Water’s Special Properties
Cohesion: water molecules stick together
Leads to high surface tension
Adhesion: water molecules stick to other charged substances

13. Other Properties of Water
Liquid water can carry substances around cells, organisms, ecosystems, or the planet
Universal solvent
Only chemical compound that exists in all three states—solid, liquid, and gas
Expands and becomes less dense as a solid