21 Non-metals

General physical properties of non metals

• low m.p. and b.p.

• Can be solid liquid or gas at room temperature

• Poor conductors of electricity and heat (except graphite)

• When solids they are weak, brittle and dull

• They have low densities

Specific properties of hydrogen

• Colorless, odorless and tasteless gas at room temperature

• Virtually insoluble in water

• The lightest known element, less dense that air

Specific properties of chlorine

• Yellow-green, poisonous gas with a strong odour

• Moderately soluble in water

• More dense than air

Specific properties of oxygen

• Colorless, odourless and tasteless gas at room temperature

• Slightly soluble in water

• Slightly denser than air

Specific properties of carbon

Has two main allotropes: Diamond and graphite

*see solid structure

Specific properties of Sulfur

Solid at room temperature

Yellow in colour

Specific properties of Nitrogen

Colourless, odourless and tasteless gas at room temperature

Virtually insoluble in water

Slightly less dense than air

Chemical properties of non metals

Ionizes when they react with metals to gain electrons forming anions

Non-metal behaves like an oxidizing agent since it removes electrons from the metal

Results in the formation of organic compounds

Reactions of non metals and metals (general)

Non metal - oxidizing agent

Metal - reducing agent

Reactions of non metals and oxygen (general)

Oxygen - oxidizing agent

Non metal - reducing agent

Most non metal oxides are … but some are …

Acidic

Basic

Reaction of hydrogen and metal

Produces metal hydrides

Reaction of hydrogen with oxygen

Burns with very pale blue flame to produce water as steam

reaction of chlorine with metal

Produces metal chlorides

reaction of oxygen with metal

Produces metal oxides

Reaction of carbon with oxygen

Burns to produce either carbon monoxide - if there’s a limited supply of oxygen, or carbon dioxide - if there’s is a plentiful supply of oxygen

reaction of sulfur with metal

Produces metal sulfides

Reaction of sulfur with oxygen

Burns with a blue flame to form sulfur dioxide

reaction of nitrogen with metal

Produces metal nitrides

Reaction of nitrogen with oxygen

Reacts with oxygen if temperature is high enough to form nitrogen monoxide

Non metals as oxidizing and reducing agents

Unless reaction with oxygen, non metals are usually oxidizing agents

Some however, can also act as reducing agents : hydrogen, carbon, sulfur, nitrogen

How to determine which method should be used to prepare a gas

Consider:

• solubility of gas in water

• Reactivity of gas with different drying agents -

• Density of the gas compared to density of air

How to know if a gas is more or less dense than air

• if RMM/2 > 14 the gas is more dense than air, if RMM/2 < 14 the gas is less dense than air

If a gas is more dense than air what do u use to prepare it

Downward delivery ( upward displacement)

If a gas is more less than air what do u use to prepare it

Upward delivery (downward displacement)

In order to be collected over water, the gas must be

Insoluble / sparingly soluble in water

Unreactive with water

Draw a diagram of apparatus used to prepare oxygen

Draw a diagram of apparatus used to prepare carbon dioxide

Draw a diagram of apparatus used to prepare Ammonia

Summary of preparation of gases table

Uses and properties of carbon dioxide

Uses of oxygen

• essential for living organisms to carry out aerobic respiration to release energy

Uses of non metals and their compounds

Harmful effects of non metals and their compounds

Disposal of waste containing plastic