chem paper 1

• This is good for higher and Foundation Tier double combined Trilogy and triple separate chemistry that's topics 1 to five atoms bonding quantitative chemistry and chemical and energy changes
• Substances are made of atoms, the different types of atoms are represented in the periodic table by a symbol
• Compound


  A substance that contains two or more different types of atoms chemically bonded together
• If there's no number after a symbol, there's an invisible 1
• Chemical reactions


  Atoms change what they're bonded to and how they're bonded
• Word equation


  A representation of a chemical reaction using words
• Chemical equation


  A representation of a chemical reaction using symbols
• Atoms are not created or destroyed in any chemical reaction, so the same number of each type of atom must be on both sides of the equation</b>
• Balancing chemical equations


  Start with atoms only in compounds, then balance remaining atoms by putting numbers in front of elements or compounds
• Mixture


  Any combination of different types of elements and compounds that aren't chemically bonded together
• Mixtures


  • Air
  • Salt water
• Solution


  A mixture of a solute dissolved in a solvent
• Separating mixtures


  1. Filtration

  2. Crystallization

  3. Distillation
• These are physical processes, not chemical reactions, because no new substances are being made
• States of matter


  • Solid
  • Liquid
  • Gas
• Melting and evaporation are physical changes, not chemical reactions, as no chemical bonds are broken
• Atom models


  • JJ Thompson's plum pudding model
  • Rutherford's discovery of the nucleus and mostly empty space
  • Bohr's discovery of electron shells/orbitals
  • Chadwick's discovery of neutrons
• Protons, electrons, neutrons


  Protons have a charge of +1, electrons have a charge of -1, neutrons have a charge of 0
• Atomic number


  The number of protons in the nucleus of an atom
• Mass number


  The total number of protons and neutrons in the nucleus of an atom
• Isotopes


  Atoms of the same element with different numbers of neutrons
• The periodic table was originally ordered by atomic weight, then later grouped by properties
• Electron configuration


  The arrangement of electrons in an atom's shells/orbitals
• Sections of the periodic table

  • Metals
  • Non-metals
• Group


  The column an atom is in on the periodic table, indicating the number of electrons in its outer shell
• Groups


  • Group 1 (alkali metals)
  • Group 7 (halogens)
  • Group 0 (noble gases)
• Ion


  An atom that has gained or lost electrons, giving it an overall positive or negative charge
• Transition metals


  Metals that can form ions with different charges
• Metallic bonding


  Bonding in metals where a lattice of positive ions is surrounded by delocalized electrons
• Ionic bonding


  Bonding between a metal and a non-metal where the metal donates electrons to the non-metal
• Covalent bonding


  Bonding between non-metals where electrons are shared
• Simple molecular/covalent structures


  Individual molecules that can mix together, with relatively low boiling points
• Giant covalent structures


  Structures where atoms are covalently bonded in a continuous network, like diamond and graphite
• Nanoparticles are between 100 and 2500 nm in size, while larger particles are called coparticles
• Surface area to volume ratio

  The ratio of the surface area to the volume of a substance, which increases as the size decreases
• Mole


  A specific number of atoms or molecules, used to compare amounts of substances
• The atoms that go in must come out in a chemical reaction, so we must balance equations
• Relative formula mass


  The sum of the relative atomic masses of the atoms in a compound
• Some reactions produce a gas product which, if it leaves the reaction vessel, will result in a seeming decrease in mass of the reactants
• Mole


  A specific number of atoms or molecules, used as a way of comparing amounts of substances