Group 1 elements Flashcards
What are group 1 elements known as?
Alkali metals
Give 3 physical properties of the group 1 elements.
- Soft (can be cut with a knife.)
- low melting point (decreases as you go down)
- Low density
What is the melting point of alkali metals?
- Low melting points.
- Decreases as you go down the group.
What are the products of an alkali metal reacting with water?
Alkali metal + water - metal hydroxide + hydrogen
What are the products of an alkali metal reacting with oxygen?
Alkali metal + oxygen –> metal oxide
What are the products of an alkali metal reacting with chlorine?
Alkali metal + chlroine –> metal chloride
What are three substances that react quickly with group 1 elements and what do they form?
- Chlorine (Metal chloride.)
- Oxygen (Metal oxide.)
- Water (Metal hydroxide + hydrogen)
Why does the reactivity of group 1 metals increase as you go down the group?
- The outer electron is less attracted to the nucleus and easier to lose.
- Greater distance between the positive nucleus and negative electron
- The outer electron is shielded from the nucleus by internal energy levels.
What group 1 elements float in water?
- Lithium
- Sodium
- Potassium
Have low density
Density increases as you go down the group
What happens to the density as you down group 1?
Density increases
What happens to the reactivity as you go down group 1?
reactivity increases
Why does the melting point decrease as you go dow group 1?
- Decrease in forces of attraction between positive ion and delocalised elctrons.
- (more shells, shielding the positive nucleus.)
Why are alkali metals stored in oil?
- Becuase they react with oxygen in the air rapidly.
Why do all Group 1 elements react in the same way?
- All have 1 electron on outer shell.
What happens when sodium reacts with water and a few drops of universal indicator are added?
- New substance formed (sodium hydroxide)
- Effervescence from Hydrogen
- Indicator green –> purple
- Sodium floats on water
- Metal gets smaller
