Compounds

Question 1

What is a compound

Answer 1

When elements react, atoms combine with other atoms to form compounds.
They’re substances formed from two or more elements.

The atoms of each are in fixed proportion throughout the compound and held together by chemical bonds

Question 2

What does making bonds involve ?

Answer 2

atoms giving away, taking or sharing electrons - only electrons are involved - nuclei of atom is not affected when bond is made

Question 3

its usually difficult to separate original elements of a compound out again - how can it be done ?

Answer 3

through chemical reactions

Question 4

A compound formed from a metal and non metal consists of

Answer 4

ions.
Metal atom loses electrons to become positive ion
Non metal will gain electrons to become negative ion
These opposite charges of ions means they’re strongly attracted to each other = ionic bonding

Examples : sodium chloride magnesium oxide calcium oxide

Question 5

A compound formed from non - metals consist of

Answer 5

molecules.
Each atom shares an electron with another atom = covalent bonding
Examples : hydrogen chloride gas, carbon monoxide, water

Question 6

The properties of a compound are usually totally

Answer 6

different from properties of the original elements.

For example: if iron ( lustrous magnetic metal ) and sulphur ( yellow powder ) react, the compound formed is a dull grey solid lump and doesn’t behave anything like either iron or sulfur.

Question 7

compounds can be represented by ..
Include Examples

Answer 7

Formulas
HCL - hydrochloric acid H2S04 - sulphuric acid
NA2CO3 = sodium carbonate