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GCSE C 1
Topic 1 - Atomic Structure and the Periodic Table
| Term | Definition |
|---|---|
| Alkali metals | The elements in Group 1 of the periodic table. |
| Atom | The smallest part of an element that can exist. All substances are made up of atoms. |
| Atomic nucleus | Positively charged object composed of protons and neutrons at the centre of every atom with one or more electrons orbiting it. |
| Atomic number | The number of protons in the nucleus. |
| Chromatography | A separation technique used to separate a mixture of chemicals by distributing the components between two phases. |
| Compound | A substance made up of two or more types of atoms chemically combined together. |
| Crystallisation | A separation technique used to produce solid crystals from a solution by evaporating the solvent. |
| Displacement | A chemical reaction in which a more reactive element displaces a less reactive element from its compound. |
| Electron | Negatively charged subatomic particle that orbits the nucleus at various energy levels. Very small relative mass (negligible). |
| Electron shell | Different energy levels in atoms occupied by electrons. |
| Element | A substance made up of only one type of atom. |
| Filtration | A separation technique used to separate solids from liquids. |
| Fractional distillation | A method of separating a mixture of substances according to their different boiling points. |
| Group (periodic table) | The columns of the periodic table represent different groups of elements. Elements with similar properties are in the same group. |
| Halogens | The elements in Group 7 of the periodic table. |
| Ion | An atom or molecule with an electric charge due to the loss or gain of electrons. |
| Isotope | Atoms of the same element with the same number of protons but a different number of neutrons. |
| Mass number | The total number of protons and neutrons in the nucleus. |
| Metals | Elements that react to form positive ions. Found to the left and towards the bottom of the periodic table. |
| Mixture | A mixture consists of two or more elements or compounds not chemically combined together. |
| Neutron | Neutral subatomic particle present in the nucleus of the atom. Relative mass of 1. |
| Noble gases | The elements in Group 0 of the periodic table. |
| Non-metals | Elements that react to form negative ions. Found towards the right and top of the periodic table. |
| Nuclear model | The nuclear atomic model stated that the mass was concentrated at the centre of the atom and that the nucleus was charged. |
| Periodic table | Table of elements arranged in order of atomic number and such that elements with similar properties are in the same column (group). |
| Plum pudding model | Atomic model devised after the discovery of the electron. The model suggests the atom is a ball of positive charge with negative electrons scattered through it. |
| Proton | Positively charged subatomic particle present in the nucleus of the atom. Relative mass of 1. |
| Relative atomic mass | An average value that takes account of the abundance of the isotopes of the element. |
| Simple distillation | A procedure by which two liquids with different boiling points can be separated. |
| Transition metals | The collection of metallic elements in the middle of the periodic table. |