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Properties of alkali metals
Soft, relatively low melting points
Reaction of lithium in water
Fizzes steadily, dissolves
Reaction of sodium in water
Melts to form a ball, fizzes rapidly, becomes smaller ball until it dissolves
Reaction of potassium in water
Quickly melts to form a ball, burns violently with sparks and a lilac flame, disappears rapidly, small explosion
What is the pattern of reactivity in alkali metals?
Reactivity increases going down the group
What is another name for the alkali metals?
Group 1
How does electron configuration relate to reactivity of group 1?
Atoms become larger, so the outer electron is further from the nucleus. The force of attraction between the nucleus and the outer electron decreases, so the outer electron is more easily lost
What colour is chlorine?
Pale green
What colour is bromine?
Brown
What colour is iodine?
Blue-black
What is the pattern in physical properties of halogens?
Low melting and boiling points
What is another name for halogens?
Group 7
What is the test for chlorine?
Damp litmus paper will be bleached white in the presence of chlorine
What happens when halogens react with metals?
They form metal halides
What can hydrogen halides do?
Dissolve in water to form acidic solutions
What is the pattern of reactivity in halogens?
They become less reactive down the group
Why are displacement reactions redox reactions?
Electrons are lost or gained by reactants
How does electron configuration relate to reactivity of group 7?
The molecules become larger, and the force of attraction between the nucleus and the outermost shell of electrons is weak, meaning it is harder to keep hold of new electrons
Why are the noble gases inert?
They have full outer shells
What is the pattern in physical properties of noble gases?
Density increases going down the group, but boiling points increase going up the group
How do the uses of noble gases depend on inertness?
They are used to not react with anything and damage the product
How do the uses of noble gases depend on low density?
It allows things to be lighter than air
How do the uses of noble gases depend on non-flammability?
They prevent object from being set on fire
What is another name for noble gases?
Group 8
