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Yr 9 Chem 1.1 &1.2
Term | Definition |
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Atom | the fundamental building block of all materials; it consists of a cluster of protons and neutrons surrounded by a cloud of electrons |
Atomic model | scientists’ representation of an atom determined by experiment and indirect observation |
Atomic number | the number of protons in a nucleus; the atomic number determines what type of atom it is |
Atomic symbol | a short-hand notation for describing an atom; it consists of the chemical symbol, atomic number and mass number |
Compound | a pure substance that is made up of two or more different types of atom chemically joined |
Crystal lattice | a grid-like structure of atoms or ions where each particle is bonded to all of its neighbouring atoms |
Electron | a small, negatively charged particle; clouds of electrons surround the nucleus of an atom |
Electron configuration | the number of electrons in each of the electron shells of an atom |
Electron shell | part of the electron cloud; it is a layer that surrounds the nucleus and can only hold a certain number of electrons |
Element | a substance made up of only one type of atom |
Isotopes | atoms that have the same number of protons but a different number of neutrons in their nucleus |
Mass number | the number of protons and neutrons in an atom |
Molecule | a cluster of atoms that makes up an element or a compound |
Neutral | having no overall charge |
Neutron | a particle with no electric charge; it is found in the nucleus of an atom |
Nucleus | a cluster of neutrons and protons at the centre of an atom |
Periodic table | table showing all 118 known types of atoms (elements) |
Proton | a positively charged particle in the nucleus |
Anion | a negatively charged ion |
Cation | a positively charged ion |
Ion | an atom that has lost or gained electrons and therefore has an electric charge |