This definitions covers Key Definitions within Atomic Structure for GCSE Chemistry. Revise Atomic Structure in Atomic Structure for GCSE Chemistry with 25 exam-style questions and 22 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 8 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Topic position
Section 8 of 13
Practice
25 questions
Recall
22 flashcards
📖 Key Definitions
Atom: The smallest particle of an element that can exist and still retain the chemical properties of that element.
Element: A substance made of only one type of atom, which cannot be broken down into simpler substances by chemical means.
Atomic number (Z): The number of protons in the nucleus of an atom. This is unique to each element.
Mass number (A): The total number of protons and neutrons (nucleons) in the nucleus of an atom.
Isotope: Atoms of the same element with the same number of protons but different numbers of neutrons, giving different mass numbers.
Relative atomic mass (Ar): The weighted mean mass of an atom of an element compared to one-twelfth of the mass of a carbon-12 atom.