6.4: Non-Metals pg. 224
Key Concepts:
1. Elements of the same column (group) of the periodic table have similar properties.
2. Metals and non-metals have characteristic physical properties.
3. Elements can be both beneficial and harmful
Properties of Non-metals
Figure 1: The non-metals (in red) are located on the right of the periodic table. The only exception is hydrogen, element number 1.
What is a Non-metal?
Non-metal: is an element that is usually a gas at room temperature or a dull, brittle solid, and a poor conductor of thermal energy and electricity.

Examples are: carbon (c), Sulfur (S), Oxygen (O),
Chlorine (Cl), Iodine (I), and Neon (Ne).
- Most Non - metals are gasses; a few are liquids and solids at room temperature.
- Solid non-metals do not have a luster (dull) like other metals. Some like sulfur have a colour.
- Solid non-metals are also brittle, and break apart with ease.
- Non-metals are poor conductors of electricity and heat.
A solid Non-metal
Sulfur is a non-metal that is brittle, yellow in colour and burns blue.
Non-metal Elements in Air
Most gases are non-metals: air is composed of…
Nitrogen 78% Oxygen 21%
Argon 0.9% Neon, Helium, Krypton, and
Carbon dioxide 0.1%
Oxygen is the most important gases. Living organism require oxygen for cellular respiration, and plants release oxygen through photosynthesis.

Figure 4: The composition of air.
To React or Not to React
The last two groups in the periodic table, group 17
(Halogens) and group 18 (Noble Gases), have distinctly different properties.
Group 17: Halogen
Elements found in group 17 are; Fluorine (F), Chlorine (Cl),
Bromine (Br), Iodine (I), and Astatine (At).
Halogens are highly reactive, they have seven electrons found in their outer electron shell.
Iodine, Bromine, and Chlorine are very poisonous.
Chlorine is used to disinfect water, Bromine has multiple uses, such as; dyes, medicines, pesticides, and photography.
Iodine is used to disinfect cuts and scrapes and purify water.

Group 18: Noble Gases
Helium (He), Xenon (Xe), Neon (Ne), and Argon (Ar).
Noble gases rarely react, because they have a complete octet in their outer electron shell.
When electricity passes through noble gases brightly coloured light is created.
Check Your Learning:
Questions 1 – 6, pg. 227
Wrap Up:
- There are fewer non-metal elements than metals.
- Most of the tings around you are made up of non-metal elements.
- Non-metals are on the right side of the periodic table.
- Like metals, non-metals have distinctive properties that make them useful.