GCSE resits

• Atom


  The smallest part of an element that can exist
• Element


  A group of atoms with the same number of protons.
• Chemical symbol


  A simple, international way of representing an element. (e.g. O represents an atom of oxygen, Na represents an atom of sodium)
• 100


  Rough amount of elements.
• Periodic table


  A data table showing all the known elements and some information about their atomic structure
• Chemical reaction


  A process that involves rearrangement of the atoms in a substance and forms new substances out of the atoms.
• Compound


  A substance made of atoms from two or more elements chemically bonded together.
• Chemical formula


  A way of representing the proportion of atoms in a compound or molecule by using symbols and numbers e.g. CO₂
• Word equation


  A way of representing a chemical reaction using the names of the compounds and elements involved and an arrow.
• Symbol equation


  A way of representing a chemical reaction using the Chemical formulae of the compounds and elements involved and an arrow.
• Group


  Vertical column on the periodic table
• Period


  Horizontal row on the periodic table
• Separation of compounds


  compound can only be separated into their component elements by electrolysis or chemical reactions (using hydrogen).
• Making compounds


  Chemical reactions needed
• Detectable energy change


  Chemical changes involving formation of one or more new substances