Group 0, 1 and 7 and Gases in the Atmosphere 2.1-2.14 Flashcards
What property do the noble gases have in common and why?
Inert/ unreactive because they have a full outer shell of electrons, so no tendency to lose and gain or share electrons
What are the physical properties of Group 1 alkali metals?
- Soft and can be easily cut
- Less dense than water
- Shiny when freshly cut, but rapidly tarnish on exposure to air
How do the Group 1 alkali metals react with water?
All react vigorously
What do reactions of alkali metals and water produce?
metal + water –> metal hydroxide + hydrogen
What do group 1 metals form when they react with oxygen?
Metal oxides
Type of oxide depends on the metal
- High reactivity metals tarnish faster as metal oxide forms faster
What is the trend of reactivity for Group 1 elements?
More reactive down the group
Can be seen with the rate of reaction with water and oxygen - faster = higher reactivity
Can use the trend to predict how other group 1 metals will react e.g. caesium more vigorous in water than potassium
Explain the trend of reactivity for group 1 metals
Atoms lose electrons more easily down the group
- All have 1 electron in their outer shell
- As you go down the group the outermost electron is in a shell that’s further from the nucleus –> attraction between electron and nucleus is less
- As you go down the atoms get bigger, the outer electron is more easily lost, and the metals are more reactive
What is the charge on a halide ion?
-1
What are the trends in physical properties in Group 7?
Down the group (as the atomic number increases) darker and higher melting and boiling points
Why do the melting and boiling points increase as you go down Group 7?
As the molecular mass increases the intermolecular forces get stronger, hence more energy is required to overcome them
What is the trend in reactivity of Group 7?
Decrease as you go down the group
What happens when halogen react with each other?
More reactive halogen will displace less reactive ones
Displacement –> transfer of electrons (oxidation or reduction)
Why does the reactivity decrease as you go down Group 7?
Gain 1 electron –> easier it is to gain this electron the more reactive the halogen will be
- Atoms get bigger down the group
- Outer shell is further from the nucleus
- There is a weaker attraction between the nucleus and the incoming electron so less tendency of gaining an electron to fill the outer shell
Describe an experiment to investigate halogen displacement reactions
- Put 3 rows of chloride, bromide and iodide (colourless halide solutions) into a dimple tile
- Now add 2-3 drops of chlorine (colourless) solution to the bromide and iodide
Add 2-3 drops of bromine (pale yellow/orange) solution to the chloride and iodide
Add 2-3 drops of iodine (orange) solution to chloride and bromide - Record observations
What are the observations for the halogen displacement reactions
Only ones that react
potassium bromide + chlorine = pale yellow
potassium iodide + chlorine = yellow/orange
potassium iodide + bromine = orange
