1. Unit 2
Chemical Categories

2. Atomic structure
All material is made up of tiny particles called atoms.
Atoms are extremely small particles.
The head of a pin contains about
atoms!

3. Mind map opportunity

4. Nucleus Consists of protons and neutrons
Protons have a positive charge and neutrons are neutral.
Nucleus
Electrons move around the nucleus in shells. The shell is the place where groups of electrons are found. Electrons are negatively charged and 1/2000 the mass / size of a proton
Add this to mind map
Note an atom is 99.99% empty space - with all its mass concentrated into the nucleus. Famous Kiwi scientist Rutherford discovered this!

5. Atom structure review Sub-atomic particle Where found Charge Proton
In the nucleus
Positive
Neutron
Neutral
Electron
Outside the nucleus
Negative

6. Silver and historically gold is placed in thin foils on Indian sweets.

7. Atomic number symbol Name 1 H Hydrogen 2 He Helium 3 Li Lithium 4 Be
An element is a substance that cannot be broken down into any other substance. Every element is made up of its own type of atom. This is why the chemical elements are all very different from each other.
The atomic number is equal to the number of protons in an atom's nucleus. The atomic number determines which element an atom is.
Atomic number
symbol
Name 1 H
Hydrogen 2 He
Helium 3 Li
Lithium 4 Be
Beryllium 5 B
Boron 6 C
Carbon 7 N
Nitrogen 8 O
Oxygen 9 F
Fluorine 10 Ne
Neon

8. Elements Each element is defined by the number of
The table shows all known elements.

9. What makes an Atom Stable? - not shake!