paper 1 chemistry

• Substance

  Stuff made of atoms
• Element

  Different types of atoms, represented in the periodic table by a symbol
• Compound

  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 reaction

  Atoms change what they're bonded to and how they're bonded
• Representing a chemical reaction

  1. Word equation

  2. Chemical equation 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 a chemical equation

  Start with atoms only in compounds, then balance other atoms by putting numbers in front of elements/compounds
• Plum pudding model of the atom

  Positive charge with lots of little electrons dotted around it
• Rutherford's model of the atom

  Positive charge (nucleus) incredibly small, electrons orbit relatively far away, atoms mostly empty space
• Bohr's model of the atom

  Electrons exist in shells or orbitals
• Proton

  Positive charge in the nucleus
• Neutron

  Neutral charge in the nucleus
• Electron

  Negative charge orbiting the nucleus
• Atomic number

  Number of protons in the nucleus, determines the element
• Mass number

  Number of protons and neutrons in the nucleus, gives the relative atomic mass
• Isotopes

  Atoms of the same element with the same number of protons but a different number of neutrons
• Relative abundance


  Percentage of each isotope in a sample of an element
• Periodic table

  Organises elements based on their properties, with gaps for undiscovered elements
• Electron configuration

  Arrangement of electrons in shells around the nucleus, up to 2, 8, 8, 2 for the first 20 elements
• Metals

  Elements to the left of the staircase on the periodic table, lose electrons to gain full outer shells
• Non-metals


  Elements to the right of the staircase on the periodic table, accept electrons to gain full outer shells
• Group

  Column an atom is in on the periodic table, tells you how many electrons in the outer shell
• Alkali metals

  Group 1 elements, have one electron in their outer shell which they readily donate
• Halogens

  Group 7 elements, have seven electrons in their outer shell and readily accept one more to gain a full shell
• Noble gases

  Group 0 elements, have full outer shells and are very unreactive
• Ionic bonding

  Metals lose electrons to non-metals, forming positive and negative ions that are attracted to each other
• Covalent bonding

  Non-metals share electrons to gain full outer shells, forming molecules
• Metallic bonding

  Metal atoms form a lattice with delocalized electrons, giving metals their conductivity and malleability
• Ionic compound

  Consists of a lattice of positive and negative ions, have high melting/boiling points and can conduct electricity when molten or dissolved
• Molecular compound

  Consists of individual molecules held together by weak intermolecular forces, have relatively low melting/boiling points and cannot conduct electricity
• Giant covalent structure

  Atoms form a continuous network of covalent bonds, like diamond and graphite, very hard and have high melting points
• Carbon allotropes

  • Diamond
  • Graphite
  • Graphene
  • Fullerenes
• Credibly strong graphite is only made of carbon as well but it's not Diamond so it's an allotrope of carbon made out of the same atoms bonded together in a different way
• Graphite

  • Consists of layers of carbons with three bonds each in a hexagonal structure
  • The spare delocalized electrons form special weak bonds between the layers which means that it can conduct electricity because the electrons can move between the layers
  • The layers can slide over each other easily which is why it's used in pencils
• Alloy

  A mixture of metals that is stronger than pure metals
• Having mixtures of metals means that we have different size atoms and that disrupts the regular lattice so layers can't slide over each other as easily
• Graphene

  A single layer of graphite
• Fullerenes


  3D structures of carbon atoms, e.g. Buckminster fullerene is a spherical football-like structure consisting of 60 carbon atoms
• Carbon nanotubes

  Fullerenes that have a tube shape