Unit 1 and 2 revision

• What is a compund: A substance that contains two or more elements chemically joined together.
• What is a mixture? contains two or more substances which are not chemically joined.
• What is Ionization Energy? Energy needed to take an electron from an atom.
• What is electronegativity? Attraction of an atom for shared electrons in a covalent bond
• What is atomic radius? distance from the nucleus to the outermost electron
• What is ionic radius? distance from outermost shell of electrons from nucleus.
• what are electrostatic forces? Forces of attraction between positively and negatively charged ions. Forces hold oppositely charged ions together.
• Why do metals become more reactive down a group? Metals react by losing electrons, a loosely held electron results in a more reactive metal.
• Why do non-metals become less reactive down a group? The number of valence shell electrons. The force of attraction between nucleus an electrons decreases, thus tendency to lose electrons increases.
• What holds ions together in an ionic bond? electrostatic forces of attraction, between oppositely charged ions.
• What holds atoms together in covalent bonds? Attractions between the shared electrons and the protons in each nucleus
• What holds ions together in metallic bonding? delocalized electrons from valence shell and attractions of positive ions.
• What is the strongest kind of electrostatic bonding? All bonds are strong.
• What are hydrocarbons? Compounds that only contain carbon and hydrogen
• What are the 2 families of hydrocarbons? Alkanes and Alkenes
• What are alkanes?


  Hydrocarbons that contain only single bonds
• What are alkenes?


  Hydrocarbons with a double carbon-carbon bond
• How do you calculate number of moles

  mass/molar mass