Matter/Structure of Atoms

• Matter: anything that occupies space and possesses mass, can be solid, liquid or gas.
• Physical properties are observed or measured: mass, volume, atomic mass, density, melting/boiling point, malleability, ductility, hardness, electron configuration, conductivity, colour, texture, shape, smell.
• Testing a physical properties will not alter the chemical form of the substance.
• Chemical properties: any of a material's properties thats evident during, or after, a chemical reaction.
• Element: substance made up of the same type of atoms.
• Molecules: substance with two or more atoms chemically combined.
• Diatomic molecule: substance with two atoms of the same element.
• Compound: two or more different types of atoms chemically combined in a specific ratio.
• Pure substance: made up of a single type of element or compound.
• Mixtures: made from two or more substances either elements, compounds or both.
• How mixture and compounds differ?

  • Substances in a mixture keep their individual properties. These properties can be used to physically separate the substance.
  • Parts of a mixture are not necessarily present in specific ratios.
• Homogeneous mixture: a substance in which two or more substances are uniformly spread out.
• Heterozygous mixture: a mixture that has an inconsistent composition, often the parts of the mixture are easily seen.
• Define isotopes.

  Isotopes: atoms with variable number of neutrons but the same number of protons.
• Define ions.

  Ions: if the number of protons and electrons are different, the atom is called an "ion" as the charges do not balance. This happens when the atoms gains or loses electrons. For example: Fe3+ - the iron atoms has lost three electrons. Cl- : the chlorine atom has gained one electron.