GCSE CHEMISTRY EXAM REVISION QUESTIONS WITH VERIFIED
SOLUTIONS LATEST 2025 UPDATE.
Define Molecule - ANSWER- A group of atoms held together by covalent bonds
e.g H2 (2 hydrogen atoms bonded together)
Chromatography - ANSWER- Method used to separate and distinguishes the different
substances within a mixture
Filtration - ANSWER- Method used to remove undissolved solids from liquids
Crystillization - ANSWER- Method used to separate dissolved solids from liquids
Distillation - ANSWER- Method used to separate a pure liquid from a mixture
Fractional distillation - ANSWER- Method to separate a liquid mixture into its individual
components
Describe the process of fractional distillation - ANSWER- 1) Mixture is heated and different
substances evaporate at different time based on their boiling point
2)Different substance condense at different portions of the fractionating column (The higher up,
the lower the temperature)
3)Each substance will travel down a different condensor and get collected in different containers
Describe the importance of purity in substances - ANSWER- Impurities in drugs or foods can
be hazardous and detrimental to our health
Mixture - ANSWER- 2 or more substances that are not chemically combined and can be
separated
,Element - ANSWER- A substance which cannot be divided into simpler substances
Compounds - ANSWER- Substances formed by the chemical combination of 2 or more
chemical elements
What is an atom made up of? - ANSWER- Subatomic particles
-Neutrons
-Protons
-Electrons
Nucleus - ANSWER- Controls cell activity
Describe the electron arrangement - ANSWER- Electrons are arranged in shells
First shell: 2 electrons
Second shell: 8 electrons
Third shell: 8 electrons
Proton properties - ANSWER- Relative mass: 1
Relative charge: +1
Electron properties - ANSWER- Relative mass:Almost 0
Relative charge: -1
Neutron properties - ANSWER- Relative mass: 1
Relative charge: 0
, Isotope - ANSWER- Atoms of the same element which have a different neutron number but
the same proton number
Ion - ANSWER- Charged particles made from an atom by the loss or gain of an electron
Why are atoms stable - ANSWER- They have an equal number of electrons and protons
Why do atoms become unstable - ANSWER- They like to have a full outer shell, they will
lose/gain electrons to achieve this
-When an atom loses or gains an electron it becomes an ion
Ionic bond - ANSWER- Strong electrostatic force of attraction between oppositely charged
ions
-Formed between metallic and non metallic elements
Describe the process of ionic bonding - ANSWER- A metal donates an appropriate amount of
electrons to a non metal to form a compound with a stable electron configuration
Describe the lattice structure of an ionic compound - ANSWER- When a metal and a non metal
react many ions are formed
-Ions do not stay in pairs, they form a regular pattern (lattice) of alternating positive and negative
ions which are held together by ionic bonds
Giant ionic structure - ANSWER- A lattice held together by the electro static forces of attraction
between positive and negative ions
SOLUTIONS LATEST 2025 UPDATE.
Define Molecule - ANSWER- A group of atoms held together by covalent bonds
e.g H2 (2 hydrogen atoms bonded together)
Chromatography - ANSWER- Method used to separate and distinguishes the different
substances within a mixture
Filtration - ANSWER- Method used to remove undissolved solids from liquids
Crystillization - ANSWER- Method used to separate dissolved solids from liquids
Distillation - ANSWER- Method used to separate a pure liquid from a mixture
Fractional distillation - ANSWER- Method to separate a liquid mixture into its individual
components
Describe the process of fractional distillation - ANSWER- 1) Mixture is heated and different
substances evaporate at different time based on their boiling point
2)Different substance condense at different portions of the fractionating column (The higher up,
the lower the temperature)
3)Each substance will travel down a different condensor and get collected in different containers
Describe the importance of purity in substances - ANSWER- Impurities in drugs or foods can
be hazardous and detrimental to our health
Mixture - ANSWER- 2 or more substances that are not chemically combined and can be
separated
,Element - ANSWER- A substance which cannot be divided into simpler substances
Compounds - ANSWER- Substances formed by the chemical combination of 2 or more
chemical elements
What is an atom made up of? - ANSWER- Subatomic particles
-Neutrons
-Protons
-Electrons
Nucleus - ANSWER- Controls cell activity
Describe the electron arrangement - ANSWER- Electrons are arranged in shells
First shell: 2 electrons
Second shell: 8 electrons
Third shell: 8 electrons
Proton properties - ANSWER- Relative mass: 1
Relative charge: +1
Electron properties - ANSWER- Relative mass:Almost 0
Relative charge: -1
Neutron properties - ANSWER- Relative mass: 1
Relative charge: 0
, Isotope - ANSWER- Atoms of the same element which have a different neutron number but
the same proton number
Ion - ANSWER- Charged particles made from an atom by the loss or gain of an electron
Why are atoms stable - ANSWER- They have an equal number of electrons and protons
Why do atoms become unstable - ANSWER- They like to have a full outer shell, they will
lose/gain electrons to achieve this
-When an atom loses or gains an electron it becomes an ion
Ionic bond - ANSWER- Strong electrostatic force of attraction between oppositely charged
ions
-Formed between metallic and non metallic elements
Describe the process of ionic bonding - ANSWER- A metal donates an appropriate amount of
electrons to a non metal to form a compound with a stable electron configuration
Describe the lattice structure of an ionic compound - ANSWER- When a metal and a non metal
react many ions are formed
-Ions do not stay in pairs, they form a regular pattern (lattice) of alternating positive and negative
ions which are held together by ionic bonds
Giant ionic structure - ANSWER- A lattice held together by the electro static forces of attraction
between positive and negative ions
