AQA GCSE Chemistry Paper 1 Already Rated A+
1. What is the fundamental building block of an element?
Answer: An atom is the smallest part of an element that can exist.
2. What defines an element, and how is it represented?
Answer: An element is a substance made up of one type of atom, and i...
1. What is the fundamental building block of an element?
Answer: An atom is the smallest part of an element that can exist.
2. What defines an element, and how is it represented?
Answer: An element is a substance made up of one type of atom, and it is represented using symbols in
the periodic table.
3. Approximately how many elements are known to exist?
Answer: There are approximately 100 elements that have been discovered and named.
4. What is a compound, and how is it different from an element?
Answer: A compound is a substance made up of two or more elements chemically combined in fixed
proportions, whereas an element is a single type of atom.
5. How are chemical reactions represented, and what do they reveal?
Answer: Chemical reactions are represented by word or symbol equations, which provide information
on the reactants, products, and chemical changes that occur.
6. Which groups of the periodic table contain sodium and potassium, chlorine, bromine, and iodine?
Answer: Group 1 (alkali metals) contains sodium and potassium, while Group 7 (halogens) contains
chlorine, bromine, and iodine.
,7. What does a chemical formula reveal about a compound?
Answer: A chemical formula provides information on which elements are bonded together and how
many atoms of each are present.
8. What is a mixture, and how does it differ from a compound?
Answer: A mixture is a combination of two or more elements or compounds not chemically bonded
together, whereas a compound is a substance formed by chemical bonds between elements.
9. Which separation techniques are used to separate different types of mixtures?
Answer: Distillation separates a mixture of two liquids, fractional distillation separates a mixture of more
than two liquids, filtration separates an insoluble solid from a liquid, chromatography separates a
mixture of colored substances, and crystallization separates a soluble solid from its solution.
10. What was the prevailing understanding of atoms before the discovery of electrons?
Answer: Before the discovery of electrons, atoms were thought to be tiny spheres that could not be
divided.
11. What was the "plum pudding" model of the atom?
Answer: The "plum pudding" model depicted atoms as balls of positive charge with negative electrons
embedded in them.
12. What experiment led to the development of the nuclear model of the atom?
Answer: Rutherford's alpha particle scattering experiment led to the development of the nuclear model.
13. What happened to the alpha particles fired at thin gold foil in Rutherford's experiment?
,Answer: Most alpha particles went straight through the gold foil, but a few were scattered in
unexpected directions.
14. What replaced the "plum pudding" model as our understanding of atomic structure improved?
Answer: The nuclear model emerged as our understanding improved, depicting atoms as having a
massive nucleus at their center.
15. Who proposed that electrons orbit the nucleus at specific distances?
Answer: Niels Bohr proposed that electrons orbit the nucleus at specific distances.
16. What did James Chadwick discover regarding atomic structure?
Answer: James Chadwick discovered neutrons, which are positively charged particles that reside in the
nucleus along with protons.In what order were the subatomic particles discovered? ✔️Electron,
proton, neutron
What is the relative charge on a proton? ✔️+1 (positive 1)
What is the relative charge on a neutron? ✔️0 (no charge)
What is the relative charge on an electron? ✔️-1 (negative 1)
Why are atoms electrically neutral? ✔️Number of protons = number of electrons
What name is given to the number of protons in an atom of an element? ✔️Atomic number
, What does the atomic number (number of protons) determine? ✔️The element. Atoms of a particular
element have the same number of protons
What is the approximate size of an atom? ✔️0.1 nm (1 x 10-10 m)
What is the approximate radius of a nucleus? ✔️1 x 10-14 m
Where is almost all the mass of an atom? ✔️In the nucleus
What is the relative mass of a proton? ✔️1
What is the relative mass of a neutron? ✔️1
What is the relative mass of an electron? ✔️Very small / negligible
What name is given to the sum of the number of protons and neutrons? ✔️Mass number
What are isotopes? ✔️Atoms of the same element with different numbers of neutrons (same number
of protons)
What is relative atomic mass, Mr, of an element? ✔️Average mass of an element's atoms, compared to
1/12th the mass of a carbon-12 atom
How is Mr calculated? ✔️Mr = (Ar 1 x abundance 1)/100 + (Ar 2 x abundance 2)/100
What is the 'electronic structure' of an atom? ✔️Shows where in the atoms the electrons are situated
How is the electronic structure of an atom represented? ✔️By numbers or a diagram
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