GCSE CHEMISTRY: ATOMIC STRUCTURE. TEST QUESTIONS WITH VERIFIED
SOLUTIONS LATEST 2025 UPDATE.
What is the definition of an atom? - ANSWER- The smallest part of a element that can exist.
What is a compound? - ANSWER- It contains atoms of two or more elements that are
chemically mixed in fixed proportions or ratios.
How are compounds represented? - ANSWER- In a chemical formula, which contains numbers
and chemical symbols.
What does a chemical formula tell you? - ANSWER- - What elements are in the compound.
- What proportion or ratio the elements are in one molecule of the compound.
How can you separate compounds into the component chemicals? - ANSWER- - Electrolysis
- Chemical Reactions
What is the relationship between the reactants and products? - ANSWER- The total mass of
the reactants will always be equal to the mass of the products as no atoms are made or lost.
What are mixtures? - ANSWER- A combination of 2 or more elements that are not chemically
combined.
What happens to the properties of components in a mixture? - ANSWER- The components
retain their original properties.
How can you separate mixtures? - ANSWER- Through physical reactions, where no new
substances are made as it is not a chemical reactions.
, Give three physical reactions. - ANSWER- - Filtration (Separate soluble solids from insoluble
solids)
- Crystallisation (Obtain soluble solids from a solution)
- Simple distillation (Obtain a solvent from a solution)
- Fractional Distillation (Separate mixtures where components have different boiling points)
- Chromatography (Separate different soluble components of a mixture)
How does crystallisation work? - ANSWER- 1) Mixture is gently warmed.
2) Water evaporates leaving crystals of pure soluble solid.
How would you analyse the purity of different water samples? - ANSWER- 1) Use indicator
or pH probe to measure the pH of the sample.
2) Place the water sample in a boiling tube with a condenser.
3) Heat the water sample to 100C so the water changes state from liquid to gas.
4) The water rises and reaches the condenser where the gas changes from gas back to liquid.
5) This liquid is collected in a beaker at the end of the condenser, called distillate.
6) When all the water has evaporated, measure the mass of the solid left in the boiling tube - which
is how impure the water sample is.
What is a use for chromatography? - ANSWER- Separate the different colours added to a fizzy
drink.
K - ANSWER-
What was discovered in 1898? - ANSWER- Thomson discovered electrons, and therefore
atoms changed.
What is the charge of a normal atom? - ANSWER- Neutrally charged.
SOLUTIONS LATEST 2025 UPDATE.
What is the definition of an atom? - ANSWER- The smallest part of a element that can exist.
What is a compound? - ANSWER- It contains atoms of two or more elements that are
chemically mixed in fixed proportions or ratios.
How are compounds represented? - ANSWER- In a chemical formula, which contains numbers
and chemical symbols.
What does a chemical formula tell you? - ANSWER- - What elements are in the compound.
- What proportion or ratio the elements are in one molecule of the compound.
How can you separate compounds into the component chemicals? - ANSWER- - Electrolysis
- Chemical Reactions
What is the relationship between the reactants and products? - ANSWER- The total mass of
the reactants will always be equal to the mass of the products as no atoms are made or lost.
What are mixtures? - ANSWER- A combination of 2 or more elements that are not chemically
combined.
What happens to the properties of components in a mixture? - ANSWER- The components
retain their original properties.
How can you separate mixtures? - ANSWER- Through physical reactions, where no new
substances are made as it is not a chemical reactions.
, Give three physical reactions. - ANSWER- - Filtration (Separate soluble solids from insoluble
solids)
- Crystallisation (Obtain soluble solids from a solution)
- Simple distillation (Obtain a solvent from a solution)
- Fractional Distillation (Separate mixtures where components have different boiling points)
- Chromatography (Separate different soluble components of a mixture)
How does crystallisation work? - ANSWER- 1) Mixture is gently warmed.
2) Water evaporates leaving crystals of pure soluble solid.
How would you analyse the purity of different water samples? - ANSWER- 1) Use indicator
or pH probe to measure the pH of the sample.
2) Place the water sample in a boiling tube with a condenser.
3) Heat the water sample to 100C so the water changes state from liquid to gas.
4) The water rises and reaches the condenser where the gas changes from gas back to liquid.
5) This liquid is collected in a beaker at the end of the condenser, called distillate.
6) When all the water has evaporated, measure the mass of the solid left in the boiling tube - which
is how impure the water sample is.
What is a use for chromatography? - ANSWER- Separate the different colours added to a fizzy
drink.
K - ANSWER-
What was discovered in 1898? - ANSWER- Thomson discovered electrons, and therefore
atoms changed.
What is the charge of a normal atom? - ANSWER- Neutrally charged.
