Atoms, Periodic Table, and Chemical Reactions

Electrons: Negative Charge

Neutrons: Neutral Charge (have the same ammount of protons and electrons)

Protons: Positive Charge

Each shell around the nucleus can have a set number of electrons.  Here is the list you need to know:

Shell & Max Number of Electrons 

First Shell = 2

Second Shell = 8

Third Shell = 8

Fourth Shell = 2

Atomic Number (proton number): Number of Protons and Electrons.

Work this out by simply looking at the number.

Mass Number (bigger one): Number of Neutrons.

Work ths out by taking the Atomic Number away from the Mass Number.  For example: 

Number of Neutons in Helium: 4 - 2 = 2

Period (the row): This tells you the number of shells filled.

Group Number: Number of outer electrons.

1) 2.5 = Nitrogen (Period 2, Group 5)

2) 2.8.6 = Sulphur (Period 3, Group 6)

3) 2.8.8.2 = Calcium (Period 4, Group 2)

- All stored in oil

Reactions with water: 

Lithium - Fizzing, floats on top (less dense), releases smoke/steam.

Sodium - Fire, fizzing, floats on top (less dense), melts into metal, popping noise.

Potassium - Fire, sparking, buzzing noise.

All make an alkali solution!

Reactions with oxygen:

Lithium - Glows red.

Sodium - Glows orange.

Potassium - Glows lilac

- They are noble gases.

- Colourless gases.  

- Very unreactive because they have 8 outer shell except for Helium.

- They have enough electrons so they do not need to react.

When 2 or more atoms joing together chemical bonds are made.  Chemical bonds can be made when:

- Atoms lose or gain electrons

- Atoms share electrons

- Metal atoms LOSE ELECTRONS to form POSITIVE IONS.

- Non metal atoms GAIN ELECTRONS to form NEGATIVE IONS.

- Ions form because there is an uneven ammount of electrons.  

- Attraction between the ions that are made are called ionic bonds.  

Convalent: Non metal atoms like hydrogen each share an electron to form a bond.  

Balancing Equations on sheet.