Atomic Structure & nature of substances

• -- Melting -> -- Boiling ->

  Solid Liquid Gas

  <- Freezing -- <- Condensing --
• Properties of Metals :

  Malleable

  Ductile

  Conductor

  Have Lustre

  Dense
• Properties of Non-Metals:

  Non-malleable

  Non-ductile

  Brittle

  Insulator

  Low Density

  No shine
• Chlorine

  Properties - Kills bacteria

  Uses - Treatment of pool water
• Iodine

  Properties - Kills Bacteria

  Uses - Medical Treatment
• Neon

  Properties - Unreactive, Emits a bright light when electricity is passed through it

  Uses - Advertising signs
• Argon

  Properties - Unreactive

  Uses - Light bulbs
• Helium

  Properties - Very low density, unreactive

  Uses - Party balloons
• Diatomic Elements include Hydrogen, Oxygen, Nitrogen and Group 7 elements
• Carbon dioxide turns limewater cloudy
• Oxygen will relight a glowing splint
• Hydrogen will make a squeaky pop with a lit splint
• What does distillation do?

  Separates mixtures that have very different boiling points
• What does chromatography do?

  Separates mixtures based on solubility
• The start point line in chromatography is often drawn in pencil because it is non-soluble
• Chromatography Rf value = distance travelled by substance / distance travelled by solvent
• Symbol: Isotopes are elements that have the same atomic number but different mass numbers
• Nucleus/atom: Isotopes are elements that have the same number of protons but different number of neutrons
• Electronic configuration: The number of numbers tells u the period, and the last number tells you the group
• Elements in the same period have the same number of shells
• Elements in the same group have the same number of electrons in the outer shell
• ionic formula is swap and drop
• Group 1 metals get more reactive as they go down the group because it gets easier to lose electrons as there's further distance between the nucleus and the outer electron (less attraction) and there's more shielding
• Group 1 elements reaction w water:

  Lithium - Sizzles, floats on water, release gas

  Sodium - Sizzles more than Lithium, melts into ball, release gas

  Potassium - Sizzles vigorously, burns a lilac flame, release gas
• Group 7 elements get less reactive as they go down the group because they need to gain an electron to get a full outer shell and the further down the group, the more shielding and distance between the outer shell and the nucleus
• Reaction between group 7 elements

  1. Displacement reaction

  2. More reactive element replaces less reactive one in a compound

  3. Each group 7 element will displace the one below it
• Displacement When fluorine is reacted with metal compounds of chlorine, iodine and bromine

  Solutions go green, dark brown and red-brown as chlorine, iodine and bromine are produced
• Displacement If iodine is reacted with the other group 7 elements

  No change in colour because it's the least reactive and no displacement occurs
• Displacement example equation

  Fluorine + sodium chloride --> chlorine + sodium fluoride
• Whats it called when an ion does not take part in the reaction?

  Spectator ion
• Group 1 + 2 elements flame tests:

  Lithium - Red

  Sodium - Orange Yellow

  Calcium - Brick Red

  Potassium - Lilac

  Barium - Apple Green
• Group 1 + 2 elements flame tests:

  Lithium - Red

  Sodium - Orange Yellow

  Calcium - Brick Red

  Potassium - Lilac

  Barium - Apple Green
• Colour of precipitate after addition of silver nitrate in halide solutions:

  Chloride - White

  Bromide - Cream

  Iodide - Yellow
• Ionic equation for when silver nitrate reacts with sodium chloride

  Ag+(aq) + Cl-(aq) --> AgCl(s)
• Ionic equation for when silver nitrate reacts with sodium bromide

  Ag+(aq) + Br-(aq) --> AgBr(s)
• Colour of precipitate after addition of silver nitrate in halide solutions:

  Chloride - White

  Bromide - Cream

  Iodide - Yellow
• Ar is the mass of an atom compared to a carbon-12 atom (atomic mass)
• in chromatography, the more soluble dye will travel further up the paper
• atom is the smallest complete particle
• element is one type of atom