GCSE Chemistry Flash Cards
Formatted as a printable flashcard PDF from your text without changing the wording.
Atomic Structure (8 cards)
Question 1. What is an atom?
Answer. The smallest part of an element. All substances are made of atoms.
Question 2. How big is an atom relative to its nucleus?
Answer. The nucleus radius is less than 1/10,000 of the atom's radius — like a pea relative
to a football pitch.
Question 3. What are the three subatomic particles and their relative
charges?
Answer. Proton: mass 1, charge +1. Neutron: mass 1, charge 0. Electron: very small
mass, charge −1.
Question 4. What is the overall electrical charge of an atom?
Answer. Atoms have no overall charge — the number of protons equals the number of
electrons.
Question 5. What was the Plum-pudding model?
Answer. The atom is a ball of positive charge with negative electrons embedded in it
(proposed before alpha-scattering).
Question 6. What did the alpha-particle scattering experiment show?
Answer. Positive particles were deflected, showing the mass is concentrated at a
positively charged nucleus.
Question 7. What is the nuclear model of the atom?
Answer. Niels Bohr proposed electrons orbit the nucleus at specific distances around a
central positive nucleus.
Question 8. Who discovered uncharged neutrons in the nucleus?
Answer. James Chadwick, about 20 years after the nuclear model became accepted.
Mass & Isotopes (5 cards)
GCSE Chemistry Flash Cards Page 1
, Question 9. What is the atomic number?
Answer. The number of protons in an atom. All atoms of the same element have the same
atomic number.
Question 10. What is the mass number?
Answer. The total number of protons and neutrons in the nucleus of an atom.
Question 11. What are isotopes?
Answer. Atoms of the same element with the same number of protons but different
numbers of neutrons.
Question 12. What is relative atomic mass (Ar)?
Answer. The weighted average mass of an atom compared to 1/12th of the mass of a
carbon-12 atom.
Question 13. How do you calculate relative atomic mass from isotope
data?
Answer. Ar = Σ(mass of isotope × % abundance) ÷ 100. E.g. Chlorine: (75×35 + 25×37)
÷ 100 = 35.5
Electrons & Ions (5 cards)
Question 14. How do electrons occupy energy levels (shells)?
Answer. The first (innermost) shell holds 2 electrons; subsequent shells hold up to 8
electrons.
Question 15. What is an electronic structure?
Answer. A notation showing the arrangement of electrons in shells. E.g. sodium = 2,8,1.
Question 16. What are positive ions (cations)?
Answer. Atoms that have lost one or more electrons, having more protons than electrons.
E.g. Na⁺.
Question 17. What are negative ions (anions)?
Answer. Atoms that have gained one or more electrons, having more electrons than
protons. E.g. Cl⁻.
GCSE Chemistry Flash Cards Page 2
, Question 18. Why is the hydrogen ion (H⁺) special?
Answer. It has no electrons at all, giving it unique chemical properties.
Compounds & Reactions (4 cards)
Question 19. What is a compound?
Answer. A substance formed from two or more elements chemically combined in fixed
proportions. Separated only by chemical reactions.
Question 20. What is the law of conservation of mass?
Answer. No atoms are lost or created in a reaction — the total mass of products equals
the total mass of reactants.
Question 21. What are coefficients in a balanced equation?
Answer. Multipliers placed before formulae to balance the number of atoms of each
element on both sides.
Question 22. Give the balanced equation for water formation.
Answer. 2H₂ + O₂ → 2H₂O (oxygen + hydrogen → water)
States of Matter (2 cards)
Question 23. What does particle theory explain about states of matter?
Answer. Changes of state from solid to liquid to gas depend on the forces between
particles and the energy supplied.
Question 24. What are limitations of the particle model?
Answer. Particles shown as hard spheres with no forces between them; does not account
for atoms being mixtures of isotopes.
Separating Mixtures (5 cards)
Question 25. What is filtration used for?
Answer. Separating insoluble solids from a liquid, e.g. sand from water.
Question 26. What is crystallisation used for?
Answer. Separating dissolved solids from a solvent, e.g. copper sulfate from water.
GCSE Chemistry Flash Cards Page 3
Formatted as a printable flashcard PDF from your text without changing the wording.
Atomic Structure (8 cards)
Question 1. What is an atom?
Answer. The smallest part of an element. All substances are made of atoms.
Question 2. How big is an atom relative to its nucleus?
Answer. The nucleus radius is less than 1/10,000 of the atom's radius — like a pea relative
to a football pitch.
Question 3. What are the three subatomic particles and their relative
charges?
Answer. Proton: mass 1, charge +1. Neutron: mass 1, charge 0. Electron: very small
mass, charge −1.
Question 4. What is the overall electrical charge of an atom?
Answer. Atoms have no overall charge — the number of protons equals the number of
electrons.
Question 5. What was the Plum-pudding model?
Answer. The atom is a ball of positive charge with negative electrons embedded in it
(proposed before alpha-scattering).
Question 6. What did the alpha-particle scattering experiment show?
Answer. Positive particles were deflected, showing the mass is concentrated at a
positively charged nucleus.
Question 7. What is the nuclear model of the atom?
Answer. Niels Bohr proposed electrons orbit the nucleus at specific distances around a
central positive nucleus.
Question 8. Who discovered uncharged neutrons in the nucleus?
Answer. James Chadwick, about 20 years after the nuclear model became accepted.
Mass & Isotopes (5 cards)
GCSE Chemistry Flash Cards Page 1
, Question 9. What is the atomic number?
Answer. The number of protons in an atom. All atoms of the same element have the same
atomic number.
Question 10. What is the mass number?
Answer. The total number of protons and neutrons in the nucleus of an atom.
Question 11. What are isotopes?
Answer. Atoms of the same element with the same number of protons but different
numbers of neutrons.
Question 12. What is relative atomic mass (Ar)?
Answer. The weighted average mass of an atom compared to 1/12th of the mass of a
carbon-12 atom.
Question 13. How do you calculate relative atomic mass from isotope
data?
Answer. Ar = Σ(mass of isotope × % abundance) ÷ 100. E.g. Chlorine: (75×35 + 25×37)
÷ 100 = 35.5
Electrons & Ions (5 cards)
Question 14. How do electrons occupy energy levels (shells)?
Answer. The first (innermost) shell holds 2 electrons; subsequent shells hold up to 8
electrons.
Question 15. What is an electronic structure?
Answer. A notation showing the arrangement of electrons in shells. E.g. sodium = 2,8,1.
Question 16. What are positive ions (cations)?
Answer. Atoms that have lost one or more electrons, having more protons than electrons.
E.g. Na⁺.
Question 17. What are negative ions (anions)?
Answer. Atoms that have gained one or more electrons, having more electrons than
protons. E.g. Cl⁻.
GCSE Chemistry Flash Cards Page 2
, Question 18. Why is the hydrogen ion (H⁺) special?
Answer. It has no electrons at all, giving it unique chemical properties.
Compounds & Reactions (4 cards)
Question 19. What is a compound?
Answer. A substance formed from two or more elements chemically combined in fixed
proportions. Separated only by chemical reactions.
Question 20. What is the law of conservation of mass?
Answer. No atoms are lost or created in a reaction — the total mass of products equals
the total mass of reactants.
Question 21. What are coefficients in a balanced equation?
Answer. Multipliers placed before formulae to balance the number of atoms of each
element on both sides.
Question 22. Give the balanced equation for water formation.
Answer. 2H₂ + O₂ → 2H₂O (oxygen + hydrogen → water)
States of Matter (2 cards)
Question 23. What does particle theory explain about states of matter?
Answer. Changes of state from solid to liquid to gas depend on the forces between
particles and the energy supplied.
Question 24. What are limitations of the particle model?
Answer. Particles shown as hard spheres with no forces between them; does not account
for atoms being mixtures of isotopes.
Separating Mixtures (5 cards)
Question 25. What is filtration used for?
Answer. Separating insoluble solids from a liquid, e.g. sand from water.
Question 26. What is crystallisation used for?
Answer. Separating dissolved solids from a solvent, e.g. copper sulfate from water.
GCSE Chemistry Flash Cards Page 3
