Groups In Periodic Table Flashcards
Group 0
Metal or non metal?
Boiling points do they increase or decrease as they go down the group? - why?
Noble gases
Non metal elements
Low boiling points
Boiling points increase going down the group- because : the atoms become larger, the intermolecular forces become stronger so the more energy is needed to overcome these forces.
Group 0 chemical properties
They are inert (unreactive) because they have a full outer shell so don’t need to react to lose/ gain electrons. They are stable.
Group 1
Physical properties
Alkali metals Soft Relatively low melting points Low densities Melting points decrease going down the group
Group 1 chemical properties
All have 1 electron in outer shell so when it reacts, it loses the electron and becomes a positive ion.
Reactivity of group 1 metals increases going down the group.
What happens when a group 1 alkali metal reacts with water
When alkali metals react with water they produce a metal hydroxide and hydrogen.
Sodium + water = sodium hydroxide + hydrogen
What’s sodium hydroxide
An alkali. A base that dissolves in water to form an alkaline solution:
The solution has a PH greater than 7 and
Turns universal indicator blue/purple
Observation of lithium, sodium and potassium when added to water
Lithium- fizzes steadily + slowly becomes smaller until disappeared
Sodium- fizzes rapidly, melts to form a ball, quickly becomes smaller until disappeared.
Potassium- burns violently with sparks and lilac flame, quickly melts to form ball, disappears rapidly, often with small explosion.
Group 1 reactions with oxygen
At room temp?
When heated?
React with oxygen from the air to make metal oxides
E.g. sodium + oxygen = sodium oxide
At room temp oxygen reacts with the surface of the metal which forms a white oxide which covers the surface.
Burn vigorously when heated and put in a glass jar of oxygen. The oxide forms as white smoke.
Group 7 physical properties
Halogens
Non-metal elements
Exist as simple molecules made from a pair of halogen atoms joined together with single covalent bonds.
Further down group 7, the higher the melting and boiling points because the atom becomes larger, there are stronger intermolecular forces, the more energy is needed to overcome these forces.
Colour and state of chlorine Cl2, bromine Br2 and Iodine I2
Chlorine- pale green, gas
Bromine- brown, liquid
Iodine- purple/ black, solid
What charged ion does a halogen form
-1, negative because it needs to gain an electron
Halogens reaction with metals
Halogens react with metals to make a salt. The salts are made of ions which are held together by ionic bonds.
E.g. sodium + chlorine = sodium chloride
Sodium and chlorine react vigorously when heated giving an orange flame and clouds of white sodium chloride.
What happens to the reactivity of halogens down a group
The reactivity decreases down the group because the shells get further away from the nucleus making it harder to gain an electron.
Halogens fluorine, chlorine, bromine and iodine reaction with iron wool.
Fluorine- cold iron wool burns to produce white iron fluoride
Chlorine- hot iron wool burns vigorously to produce orange/brown iron chloride.
Bromine- hot iron wool burns quickly to produce red/brown iron bromide
Iodine- hot iron wool reacts slowly in iodine vapour to produce grey iron iodide.
Halogens reacting with non-metals
Halogens react with non-metals such as hydrogen. When a halogen reacts with hydrogen it produces a compound called a hydrogen halide.
E.g. Hydrogen + chlorine = hydrogen chloride
