Chemistry IGCSE Revision || with certified answers.
Ionic Bonding correct answers Between a metal and a non-metal
1) soluble in water - polar water molecules are attracted to the giant 3D crystal lattice and break
it apart
2) conduct electricity when molten - when molten, the bonds have broken and the electrons are
free to move and carry charge
3) normally solids at room temperature - ions held in a fixed position by strong bonds
4) higher melting and boiling points - strong ionic bonds in a 3D crystal lattice that take much
energy to break
Covalent Bonding correct answers Between 2 non-metals
1) insoluble in water
2) brittle solids, liquids or gases at room temperature
3) don't conduct electricity when molten
4) lower melting and boiling points - molecules are held together by weak intermolecular forces
that are easy to break
Diatomic Gases: a nitrogen molecule has a triple bond, a carbon dioxide molecule has two
double bonds, an oxygen molecule has two double bonds.
Cation correct answers Positive Ion
Anion correct answers Negative Ion
Metallic Bonding correct answers An array of positive ions in a sea of delocalised electrons.
Most metals are hard and have high melting points. Good conductors of heat. Malleable and
ductile.
, Solids correct answers Particles are closely packed in a regular structure. The only movement the
particles have is vibration.
Liquid correct answers Particles are still mainly touching but some gaps have appeared. Liquids
are usually less dense that the solid.
Gas correct answers Particles are much further apart and there are almost no forces of attraction
between them.
Changes of State correct answers Solid --> Liquid - Melting
Liquid --> Solid - Freezing
Liquid --> Gas - Boiling
Gas --> Liquid - Condensing
Solid --> Gas and Gas --> Solid - Sublimation
Diffusion correct answers The spreading out of particles in a gas or a liquid. The lighter the
particles, the faster they diffuse. This is demonstrated by the experiment with cotton wool soaked
in ammonia solution at one end of a tube and cotton wool soaked in HCl at the other end. The
white cloud of ammonium chloride forms closer to the hydrochloric end. Also to speed up
diffusion, you can stir a liquid or heat up the liquid or gas.
Isotope correct answers Atoms that have the same atomic number but different mass numbers.
They have the same number of protons but a different number of neutrons. Number of electrons
= number of protons.
Alloys correct answers An alloy is a mixture of metals, e.g. brass is a mixture of copper and zinc.
In an alloy, the different metals have slightly differently sized atoms. This breaks up the regular
arrangement and makes it more difficult for the layers to slide.
Giant Ionic Structures correct answers All ionic compounds are huge lattices which is a regular
array of particles. e.g. sodium chloride
Ionic Bonding correct answers Between a metal and a non-metal
1) soluble in water - polar water molecules are attracted to the giant 3D crystal lattice and break
it apart
2) conduct electricity when molten - when molten, the bonds have broken and the electrons are
free to move and carry charge
3) normally solids at room temperature - ions held in a fixed position by strong bonds
4) higher melting and boiling points - strong ionic bonds in a 3D crystal lattice that take much
energy to break
Covalent Bonding correct answers Between 2 non-metals
1) insoluble in water
2) brittle solids, liquids or gases at room temperature
3) don't conduct electricity when molten
4) lower melting and boiling points - molecules are held together by weak intermolecular forces
that are easy to break
Diatomic Gases: a nitrogen molecule has a triple bond, a carbon dioxide molecule has two
double bonds, an oxygen molecule has two double bonds.
Cation correct answers Positive Ion
Anion correct answers Negative Ion
Metallic Bonding correct answers An array of positive ions in a sea of delocalised electrons.
Most metals are hard and have high melting points. Good conductors of heat. Malleable and
ductile.
, Solids correct answers Particles are closely packed in a regular structure. The only movement the
particles have is vibration.
Liquid correct answers Particles are still mainly touching but some gaps have appeared. Liquids
are usually less dense that the solid.
Gas correct answers Particles are much further apart and there are almost no forces of attraction
between them.
Changes of State correct answers Solid --> Liquid - Melting
Liquid --> Solid - Freezing
Liquid --> Gas - Boiling
Gas --> Liquid - Condensing
Solid --> Gas and Gas --> Solid - Sublimation
Diffusion correct answers The spreading out of particles in a gas or a liquid. The lighter the
particles, the faster they diffuse. This is demonstrated by the experiment with cotton wool soaked
in ammonia solution at one end of a tube and cotton wool soaked in HCl at the other end. The
white cloud of ammonium chloride forms closer to the hydrochloric end. Also to speed up
diffusion, you can stir a liquid or heat up the liquid or gas.
Isotope correct answers Atoms that have the same atomic number but different mass numbers.
They have the same number of protons but a different number of neutrons. Number of electrons
= number of protons.
Alloys correct answers An alloy is a mixture of metals, e.g. brass is a mixture of copper and zinc.
In an alloy, the different metals have slightly differently sized atoms. This breaks up the regular
arrangement and makes it more difficult for the layers to slide.
Giant Ionic Structures correct answers All ionic compounds are huge lattices which is a regular
array of particles. e.g. sodium chloride
