| What are the Physical Properties of the Noble Gases? | - low boiling points (helium - lowest)
As you go down:
- attractive forces between them become stronger
- atoms become larger
- the intermolecular forces between atoms get stronger
- more energy needed to overcome these forces |
| Why are the noble gases inert(unreactive)? | They have a full outer shell ∴ stable electron arrangements ∴ they have no tendency to loose or gain electrons and are unreactive |
| What are the physical properties of the alkali metals (Group 1)? | are soft (can be cut with a knife)
have relatively low melting points
have low densities |
| Why do elements in a group have similar chemical properties? | They have the same amount of electrons on their outer shell |
| What happens when alkali metals react with water (give an example)? | alkali metal + water → metal hydroxide + hydrogen |
| What happens when sodium reacts with water | sodium + water → sodium hydroxide + hydrogen
Sodium hydroxide is an alkali and a base that dissolves in water to form an alkaline solution which:
- has a pH greater than 7
- turns universal indicator solution blue or purple |
| What happens when the alkali metals react with oxygen? | 1) Room temp - oxygen reacts with metals surface forming a white oxide which covers the surface (metal below the surface doesn't react)
2) When heated - burn vigorously, oxide forms as white smoke
3) The reactivity of these elements increase as you go down |
| What happens when the alkali metals react with chlorine? | Vigorously producing chlorides
Room temp - chlorides are white solids that dissolve in water forming colourless solutions
Reactions get more vigorous as you go down |
| Explain the trend in reactivity as you go down group 1. | Going down:
- the atoms become larger
- the outer electron becomes further from the nucleus
- the force of attraction between the nucleus and the outer electron decreases
- the outer electron is lost more easily
AND: the more easily it loses its electron(ion formed), the more reactive the metal |
| Describe the colour and physical states of Chlor/Bro/Iodine at room temp? | View image: |
| Why do melt/boiling points increase the further you go down in Group 7? | - the molecules become larger
- the intermolecular forces become stronger
- more energy is needed to overcome these forces |
| How do halogens react with metals? | 1) halogens + metal -> salt
2) Salts are made of ions which are held by ionic bonds
3) The reactivity of elements decrease as you go down |
| How do halogens react with non-metals (give an example)? | When reacting with HYDROGEN:
- produce a compound: hydrogen halide
- which are gases at room temp.
- dissolve in water forming acidic solutions
Image shows what happens when halogens react with hydrogen: |
| Explain the trend in reactivity of the Halogens | Going down:
- the atoms become larger
- the outer shell becomes further from the nucleus
- the force of attraction between the nucleus and the outer shell decreases
- an outer electron is gained less easily
- the halogen becomes less reactive |
| Explain displacement reactions of Group 7 (give an example) | More reactive halogens can displace less reactive ones from solutions of its salt
EXAMPLE:
chlorine + potassium iodide → potassium chloride + iodine |
