Chemistry

• Mass number


  The top number and describes the amount of protons + neutrons
• Atomic number


  The bottom number - and shows how many protons there are
• Mass number - atomic number = neutrons
• Overall charge of an atom

  Determined by the same number of protons and electrons - this means the atom is neutral
• Atoms have different numbers of protons and electrons
• Positive or negative charge


  Determined by the different amount of protons and electrons
• Electron shell configuration


  1. The first electron shell holds 2 electrons

  2. The next shell holds 8 electrons

  3. The next shell also holds 8 electrons, etc.
• Formula for sulphuric acid

  H2SO4
• Formula for hydrochloric acid

  HCL
• Formula for nitric acid


  HNO3
• Formula for sodium hydroxide

  NaOH
• Formula for potassium hydroxide


  KOH
• Formula for calcium hydroxide

  Ca(OH)2
• Word equation for neutralisation

  Acid + Base --> Salt + Water
• What salt does hydrochloric acid make

  chloride salts
• What salt does sulphur acid make

  sulphate salts
• What salt does nitric acid make

  nitrate salts
• What is strong acid

  pH below 3, red
• What is weak acid

  Between pH 3-6, orange/yellow
• What is neutral


  7, green
• What weak alkali


  Between pH 8-11, blue
• What is strong alkali

  pH 11-14, purple
• What is excess water removed by

  Evaporation
• What is excess base removed by

  Filtration
• What does excess base/metal mean

  All acids are neutralised
• What can insoluble bases dissolve in

  Acid
• Proton mass, charge, location

  Mass: 1

  Charge: +1

  Location: In nucleus
• Neutron mass, charge, location

  Mass: 1

  Charge: 0

  Location: In nucleus
• Electron mass, charge, location

  Mass: 0.0005

  Charge: -1

  Location: Orbit around nucleus
• Electron configuration


  2, 8, 8 (electron shells fill from inside out)
• Why are atoms not charged

  - Atoms have equal numbers of protons and electrons which lead to not charge
• Why are ions charged

  - Ions do not have equal numbers of protons and electrons which lead to charge

  - If there are more electrons than protons, it will be negatively charged

  - If there are more protons than electrons, it will be positively charged
• How many electrons are there in group 1

  1 electron in outer shell, they will loose this to form 1+ ions with a full outer shell
• How many electrons are there in group 2

  2 electrons in outer shell, they will loose this to form 2+ ions with a full outer shell
• How many electrons are there in group 3

  3 electrons in outer shell, they will loose this to form 3+ ions with a full outer shell
• How many electrons are there in group 5

  5 electrons in outer shell, they will gain 3 electrons to form 3-ions with a full outer shell
• How many electrons are there in group 6

  6 electrons in outer shell, they will gain 2 electrons to form 2- ions with a full outer shell
• How many electrons are there in group 7

  7 electrons in outer shell, they will gain 1 electron to form 1- ions with a full outer shell
• What is the atomic number

  Bottom number that tells you the number of protons and electrons (they are the same)
• What is the mass number


  Top number that tells you the number of protons and electrons added together