yr 8 - chem intro

Substance - Elements

• All thing are made up of atoms - building blocks of every substance

Elements

• Made up of just one type of atom

• Has a unique set of characteristics - its properties

• Represented by a chemical symbol, H - Hydrogen, O - Oygen

Properties determine whether an element is classified as metal or non-metal and how they are used

Metals - Metallic Elements

Metals share common properties

• Lustrous - shiny or can be polished to make shiny

• Solid at room temperature

• Good conductors of heat and electricity

• Good conductors of heat and electricity

• Malleable - bent or hammered into sheets

• Ductile - stretched into wires

Non-Metals - Non metallic elements

Non metals share common properties:

1. Tend to be dull

2. Insulators (non-conductors) of heat and electricity

3. Brittle - break when force is applied

Arrangement of atoms in elements

• Single atoms - monoatomic elements

  • Rare

  • Only in 6 elements - He, Ne, Ar, Kr, Xe, Rn

  • Non metalic gases

  • Also known as Noble gases

• Cluster of atoms - molecules

  • Most non metal elements

  • Molecular elements

    • All the molecules are identical, same size, shape, number and type of atom

  • Oxygen (O2), Nitrogen (N2), Phosphorus (P4), Sulfur(S6)(ring shaped)

• Crystal lattices - gird like structures with repeated patters

  • All metallic elements

  • Only a few non metallic elements

  • Graphite - carbon atoms