1. Compounds, Ions, and Molecules
February 25 & 26

2. Electrons
Electrons in the outer shell of an atom, may jump or be shared with the outer shell of another atom.
This is what makes all chemical reactions possible!
When one or more electrons from one atom jump or are shared with another atom, we have a molecule!

3. Compounds
Compounds are when electrons from one atom jump or are shared with another atom.
The difference between compounds and molecules?
Molecules can be bonds between the same element.
We must have two different elements for compounds.
The compound has properties that are different from the original elements.

4. Salt Example!
Sodium- A shiny metal that catches fire in water and tarnishes quickly in air.
Chlorine- A poisonous green gas.

5. Cont.

6. Salt Example
An electron from sodium’s outer shell jumps to chlorine’s outer shell.
Sodium now has 10(-) and 11(+)…positive charge!
Chlorine now has 18(-) and 17(+)…negative charge!
Atoms with a positive or negative charge are called ions.

7. Salt Example
When Na gives up an electron, it becomes a positive ion written as Na+
When Cl receives the electron, it becomes a negative ion written as Cl-
Why do the ions stay together to form salt?
Opposites attract!
Salt is an example of an ionic compound because an atom is giving away an electron.
This is different from molecular compounds when atoms share their electrons.

8. Molecular Compound
O2 is a molecular compound because the oxygen atoms share electrons.
Water is a molecular compound because the 2 hydrogens and 1 oxygen share their electrons.