Atoms elements and compounds

• Atomic Structure and the Periodic Table

  • Atoms, Elements, Compound and Mixtures
• Atom


  The smallest part of an element that can exist
• Element


  A substance that contains only one sort of atom
• Mixture


  A physical combination of two or more substances
• Compound


  A substance that contains atoms of two or more elements, which are chemically combined in fixed proportions
• All substances are made of atoms
• There are about 100 different elements
• Elements are displayed in the periodic table
• The atoms of each element are represented by a different chemical symbol
• Most substances are compounds
• Chemical formula


  A combination of numbers and chemical symbols that represents a compound
• Chemical formulae show the different elements in a compound and how many atoms of each element one molecule of the compound contains
• Compounds can only be separated into their component elements by chemical reactions or electrolysis