Lesson 1: Atoms

Sub-atomic Particles

All atoms are made of three particles, we call these subatomic particles.

"Sub-atomic"

• "Sub" meaning part of

• "Atom" meaning indivisible particle

These particles are

1. Protons

2. Neutrons

3. Electrons

Properties of the Subatomic Particles

Each subatomic particle has three properties we are concerned about these are:

• Mass

• Charge

• Location

Electrons

• Mass = ~0

• Charge= -

• Location= Electron shells/cloud

Protons

• Mass= ~1

• Charge= +

• Location= Nucleus

Neutrons

• Mass= ~1

• Charge= neutral/no charge

• Location Nucleus

Elements

Each element has a unique structure depending on the numbers of each subatomic particle.

Directly these particles change the atomic number, the atomic mass and the charge of the atom.

Indirectly the particles change atom size, metallic character and reactivity.

Elemental Symbols

On the Periodic Table each element has its own symbol that displays a lot of information.

The smallest number displays atomic number

• This tells you the number of protons in the element

The 1-2 letter word tells you the atomic symbol

• These are shortened ways of referring to an element

• Sometimes the symbol doesnt always match the name, this is becuase the ancient Greek/Roman name may be being used

The full word is the name of the element

•  Even if we see the symbol we need to read it out as the name

The larger number is the atomic mass

• This tells us the number of protons and neutrons added together