Groups 1 and 7 Flashcards
What are group 1 elements called?
Alkali Metals
List 4 physical properties of Alkali Metals
1) Good conductors of electricity and heat
2) Soft, can be cut with a knife
3) In comparison to other metals have a low melting & boiling points
4) Low density float on water (Li,Na,K)
What happens when an alkali metal reacts with oxygen?
Shiny surface quickly becomes dull
What is the generic formula between an alkali metal(M) and oxygen when it burns?
4M+O2 → 2M2O
What is formed when an alkali metal burns in oxygen?
Its oxide is formed
What happens to an alkali metal when it reacts with water?
Metal hydroxide and hydrogen are formed
What is the generic formula between an alkali metal(M) and cold water?
2M+2H20 → 2MOH+H2
What type of reaction is the reaction between an alkali metal and cold water?
Exothermic
What observations can be made when Li reacts with cold water?(4)
1) Bubbles of gas
2) Moves around on the surface
3) Hissing sound
4) Gets smaller; eventually disappears
What observations can be made when Na reacts with cold water which are different to Li?(1)
Melts into a shiny ball
What observations can be made when K reacts with cold water which are different to Li?(2)
1) Melts into a shiny ball
2) Burns with a lilac coloured flame
Explain why sodium chloride has a high melting point?
Ionic structure, therefore lots of force is required to separate the ions as they have electric forces of attraction between them
Using Na as an example explain what is meant by the metallic bond
Strong electrical forces of attraction between mobile electrons and immobile positive metal ions
Put Li,Na,K in order of the reactivity starting with most reactive first
K,Na,Li
Why is K more reactive than Li?
Because it has electrons further away from the nucleus therefore there is less force on them, therefore it is easier to pull them away from the nucleus.
