Symbols and the Periodic Table :

A. Symbols

· all matter is made of tiny particles called atoms.

· an atom is something that can not be broken down any further and still keep its properties.

· Each element has its own kind of atom

· compounds have more than 1 kind of atom

· molecules have two or more atoms joined together

· to make life easy for scientists, we use symbols for elements

· the first letter is ALWAYS capitalised

· if there is a second letter, it is NOT capitalised.

B. The Periodic Table :

· contains a list of all of the elements known at this time

· the elements on the periodic table are arranged according to similar properties.

· The easiest way to break up the periodic table using properties is to separate it into METALS and NON METALS.

Metals :

· shiny

· ductile (can be stretched into wires) and malleable (bendable and able to pound into sheets)

· conductors (they can conduct heat and electricity)

· all elements to the left of the “staircase” on the periodic table.

Non Metals

· not shiny

· not ductile or malleable

· not conductors

· all elements to the right of the “staircase” on the periodic table.

3. Formulas

· are used to describe molecules and compounds

· are combinations of symbols and numbers

· they tell us how many of each type of atom is in a compound

Examples

H₂O (water) has 2 Hydrogen and 1 Oxygen atom

NaCl (salt) has 1 Sodium and 1 Chlorine atom

CuSO₄ (copper sulphate) has 1 Copper, 1 Sulphur and 4 Oxygen atoms

Try these :

1. NaHCO₃ Sodium Bicarbonate (baking soda)

2. CaCO₃ Calcium Carbonate(chalk)

3. H₂O₂ Dihydrogen Dioxide (hydrogen peroxide)

Answers :

1. One Sodium, One Hydrogen, One Carbon and Three Oxygen atoms

2. One Calcium, One Carbon, and Three Oxygen atoms

3. Two Hydrogen atoms and Two Oxygen atoms.