Topic 6 - Groups In The Periodic Table Flashcards
What are the group 1 metals?
Alkali metals
How can elements be classified as alkali metals based on their position on the periodic table?
They all have one outer electron on their outer shell so they’re group 1
How can elements be classified as halogens based on their position on the periodic table?
They all have 7 electrons in their outer shell so are in group 7
How can elements be classified as noble gases based on their position on the periodic table?
They have a full outer shell so are group 0
Physical properties of alkali metals
Low melting and boiling points
Very soft
Describe the reaction of lithium with water
Lithium will move around the surface, fizzing furiously
Describe the reaction of sodium with water
Move around quickly and fizz. Also melts in the heat of reaction
Describe the reaction of potassium with water
Moving around violently and fizzes. Gets hot enough to ignite the hydrogen produced
Describe the pattern in reactivity of the alkali metals.
Reactivity increases down the group
Explain the pattern of reactivity in group 1 in terms of electronic configurations
Group 1 lose their outer electron to form +1 ion. As you go down the outer electron is more easily lost because it’s further from the nucleus so it’s attraction is weaker and less energy needed to remove it
What is chlorine at room temperature?
Green gas
What is bromine at room temperature?
Red brown liquid which gives off an orange vapour
What is iodine at room temperature?
Dark grey crystalline solid which gives off a purple vapour when heated
What are halogens?
Diatomic molecules sharing one pair of electrons in a covalent bond giving both atoms a full outer shell.
What are the trends as you go down in group 7?
As you go down the melting and boiling points of halogens increase. Going from gas to solid. Also colours get darker
Describe the chemical test for chlorine
Hold a piece of damp blue litmus paper over chlorine. At first it turns red and then the chlorine will bleach the litmus paper white.
Explain the relative reactivity of the halogens in terms of
electronic configurations
Halogen atom only gains one electron to form 1- ion. As you go down halogens become less reactive because it gets harder to attract the extra electron to fill outer shell when it’s further away from nucleus.
What happens when halogens react with metals?
They react vigorously to form salts called metal halides:
Sodium + chlorine -> sodium chloride
What happens when halogens react with hydrogen?
They form hydrogen halides. They’re soluble and can dissolve in water to form acidic solutions:
Hydrogen + chlorine -> hydrogen chloride
What is a displacement reaction?
When a more reactive element displaces a less restive element from a compound
What are the halogen displacement reactions?
They’re redox reactions. The halogens gain electrons (reduction) whilst halide ions lose electrons (oxidation)
Why are noble gases (group 0) inert?
They have a full outer shell of electrons so they don’t need to give up or gain electron
What are the uses of noble gases due to their non flammability?
Argon is used in filament lamps so it stops the hot filament from burning.
Some are used in flash photography to stop flash filament from burning.
What are the uses of noble gases due to their inertness?
Used to protect metals that are being welded to stop the hot metal reacting with oxygen.
What are the uses of noble gases due to their low density?
Helium used in balloons + airships as it has lower density than air to so it floats.
What are the patterns in the properties of group 0?
As you go down group 0 BP, MP + density increase due to intermolecular forces becoming stronger
Describe the noble gases
They’re a colourless gas at room temperature
Monatomic - made up of single atoms
Inert
