Chemistry (paper 2) 📍 Flashcards
What are group 1 elements called?
Alkali metals
What are group 7 elements called?
Halogens
What are group 0 elements called?
Noble gases
Inert meaning
Unreactive
Noble gas characteristics
• Exist as single atoms
• Have a full outer shell = stable arrangement of electrons
• Therefore they’re inert and don’t easily form molecules
• Non - flammable
What is helium used for and why?
• Useful for airships
• Has a very low density and is non-flammable
What is neon used for and why?
• Useful for making illuminated signs
• Neon produces red/orange light when electricity is passed through it
What is argon used for and why?
• Used when an inert atmosphere is needed as it won’t react with anything
• Eg Argon is used to replace oxygen so that the oxygen doesn’t react with (or corrode) reactive metals being made
Alkali metal properties
• They’re reactive
• They’re soft
• They have low melting and boiling points
How do alkali metals react with water?
• They react with water to produce a metal hydroxide (alkali) and hydrogen
• Metal floats on surface as its less dense than water
• Metal fizzes as hydrogen gas is given off
• Universal Indicator goes blue/purple (pH 14) as alkaline metal hydroxide is formed
General equation for metal reacting with water
metal + water —> metal hydroxide + hydrogen
What happens to reactivity as you go down group 1 and how is it shown?
• The reactivity increases
• The amount of fizzing increases
• The reaction is more vigorous
Why do alkalis get more reactive as you go down group 1?
• As you go down the group there is a greater distance between the nucleus and outer electron
• Therefore there is less electrostatic attraction and the electron is more easily lost
Halogen charactersistics
• Exist as molecules made of pairs of atoms
• As you go down the group, the size of the molecules increases
• Therefore the melting and boiling point increases
Test for chlorine gas
When damp, blue litmus paper gets bleached white
