What is the shorthand way of representing elements?

• Chemical names

• Chemical symbols

• Chemical numbers

• Chemical strucutre

What does a chemical symbol consist of?

• Only one letter

• two numbers

• one or two letters

• four letters

The first letter of the chemical symbol is always a.......

• Capital

• Number

• Lower case

• subscript

The second letter of a chemical symbol is always a ........

• Upper case

• Lower case

• subscript

• superscript

• Some elements have symbols that are simply the first letters of their name:

O C N

What are the elements indicated by these letters?

• Oxygen

  Carbon

  Nitrogen

• Oxygen

  Cobalt

  Nitrogen

• Ozone

  Carbon

  Nitrogen

• Oxygen

  Carbon

  Nickel

• Some elements have symbols that come from the first and second or first and third letters of their names:

Ca Mg Ne

What are the elements indicated by these letters?

• Carbon

  Magnesium

  Nitrogen

• Calcium

  Magnesium

  Nylon

• Calcium

  Magnesium

  Neon

• Carbon

  Manganise

  Neon

• There are also some elements that have symbols that are not linked to their names.

Pb Au

What are the elements indicated by these letters?

• Lithium

  Gold

• Potasium

  Amber

• Lead

  Gold

• Argon

  Iron

The formula of a compound provides two key pieces of information

• Name and number of atoms of each element

• Name and size of nucelus of each atom

• Size and number of atoms of each element

• Name and weight of the symbol

Sodium chloride contains the elements sodium (Na) and chlorine (Cl). The formula contains 2 atoms in total (1 × Na and 1 × Cl).

Magnesium bromide contains the elements magnesium (Mg) and bromine (Br). The formula contains 3 atoms in total (1 × Mg and 2 × Br).

• MgBr2
• MgBr₂

• MGBr2

• 2MGBr