Definitions

• Atomic Number


  The number of protons in the nucleus of an atom
• Bohr Model


  Describes an atom as a small dense nucleus with electrons orbiting around the nucleus. This model explains different periodic properties of atoms
• Electron


  A negatively charged subatomic particle which orbits the nucleus at various energy levels. The relative mass of an electron is 1/1836
• Ion


  A charged atom or molecule
• Isotopes


  Atoms of the same element with the same number of protons and electrons but different numbers of neutrons. Isotopes of an element have different masses
• Mass Number


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


  An instrument which gives accurate information about relative isotopic mass and the relative abundance of isotopes
• Neutron


  A neutral subatomic particle found in the nucleus of an atom. The relative mass of a neutron is 1
• Proton


  A positively charged subatomic particle found in the nucleus of an atom. The relative mass of a proton is 1
• Relative Abundance


  The amount of one substance compared with another
• Relative Atomic Mass


  The weighted mean mass of an atom compared with 1/12th mass of an atom of carbon-12
• Relative Isotopic Mass


  The mass of an atom of an isotope compared with 1/12th mass of an atom of carbon-12
• Atomic (Proton) Number


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


  The mass of the formula unit of a compound with a giant structure. For example, NaCl has a relative formula mass of 58.44 g mol^-1

  
• Bohr Model


  Describes an atom as a small dense nucleus with electrons orbiting around the nucleus. This model explains different periodic properties of atoms
• Cations


  Positively charged ions
• 1. block


  The part of the periodic table in which the elements have their highest energy electron in a d-orbital
• Relative Molecular Mass (Mr)


  The mass of a simple molecule
• Ammonium ion


  An ion with the formula NH4+
• Electron Configuration


  The arrangement of electrons into orbitals and energy levels around the nucleus of an atom / ion
• Carbonate


  An ion with the formula CO3^2-
• First Ionisation Energy


  The removal of one mole of electrons from one mole of gaseous atoms. Factors which affect the first ionisation energy are: the strength of attraction between the electron and the nucleus, the nuclear charge and the atomic radius. There is a small decrease in first ionisation energy due to s- and p-subshell energies (between Be and B) and p-orbital repulsion (between N and O)
• Giant Covalent Lattice


  A network of atoms bonded by strong covalent bonds (e.g. carbon (diamond, graphite and graphene) and silicon). Giant covalent lattices typically insoluble with a high melting and boiling point due to the presence of strong covalent bonds. They are also poor electrical conductors as they don't contain mobile charged particles
• Hydroxide


  An ion with the formula OH-
• Giant Metallic Lattice Structure

  The structure of all metals, made up of cations and delocalised electrons. Giant metallic structures are typically insoluble with a high melting and boiling points due to strong electrostatic forces of attraction between cations and electrons. Metals are good electrical conductors due to the presence of delocalised electrons (mobile charges)
• Ionic Compound


  A compound which is made up of oppositely charged ions that are held together by electrostatic forces
• Group


  A column in the periodic table
• Nitrate


  An ion with the formula NO3-
• Melting Point


  The temperature at which a solid melts and becomes a liquid. This increases from giant metallic to giant covalent structures then decreases to simple molecular structures
• Metallic Bonding


  Strong electrostatic attraction between cations and delocalised electrons
• Silver ion


  Has the formula Ag+
• 1. block


  The part of the periodic table in which the elements have their highest energy electron in a p-orbital
• Period


  A row in the periodic table
• State symbols


  Symbols within a chemical equation which indicate the state of each compound under the reaction conditions. (g) gaseous, (l) liquid, (s) solid and (aq) aqueous
• Periodicity


  A repeating trend in physical and chemical properties across the periods of the periodic table
• Sulfate


  An ion with the formula SO4^2-
• Zinc ion


  Has the formula Zn^2+
• 1. block


  The part of the periodic table in which the elements have their highest energy electron in an s-orbital
• Amount of substance


  The quantity that has moles as its units, used as a way of counting atoms. The amount of substance can be calculated using mass (n = m/M), gas volumes (n = pV/(RT)) or solution volume and concentration (n = CV)
• Successive Ionisation Energies


  The energy required to remove each electron one-by-one from one mole of gaseous atoms / ions