CAIE A Level Chemistry 9701 · Atomic structure
An atom is described by its atomic number, Z, and its mass number, A.
Compare the terms atomic number and mass number. In your comparison, state what each number counts, what it tells you about the protons, neutrons and electrons in the atom, and why the mass number is generally greater than the atomic number.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.