2 - Chemistry of the Elements Flashcards
What are periods?
- Rows across
- Properties change as you go along
What are groups?
- Columns going across
- Similar chemical properties because of the electrons on the outer shell
- Gradually change as you go down and the atomic number increases
What are metals in the periodic table?
The majority (including aluminium)
What are non-metals in the periodic table?
The minority (including oxygen and boron)
Group 0 properties
- Noble gases
- All inert
- Full outer shell of electrons
Group 1 properties
- The alkali metals
- Reactivity increases going down
- All react similarly with water
How do group 1 react with water?
e.g. sodium + water –> sodium hydroxide + hydrogen
solid + liquid –> aqueous + gas
Describe an experiment to show alkali metals reacting with water
- Put a small lump in a beaker with water
- Universal indicator shows the colour change (green to blue to purple (alkaline))
- Use a stopwatch to time how long it takes to fizz out
- As you go down the group it will react more vigorously and quicker
Describe an experiment to show alkali metals reacting with water
- Put a small lump in a beaker with water
- Universal indicator shows the colour change (green to blue to purple (alkaline))
- Use a stopwatch to time how long it takes to fizz out
- As you go down the group it will react more vigorously and quicker
Group 7 properties
- Halogens
- Colour gets darker as you go down
- Solidify as you go down
- boiling point increases
Group 7 properties
- Halogens
- Colour gets darker as you go down
- Solidify as you go down
- boiling point increases
- Reactivity decreases (shell with missing electron in further away from nucleus)
What happens to hydrogen chloride gases in water?
- It dissociates
- The ions split into H+ ions and Cl- ions
- Hydrochloric acid is formed
- This doesn’t happen in methylbenzene because it isn’t acidic
What are the state symbols in a halogen displacement reaction?
All aqueous
What is an oxidising agent?
Something in a reaction that accepts electrons and gets reduced (the more reactive element is normally the oxidising agent)
What is a reducing agent?
Something that loses electrons and gets oxidised (the less reactive element is normally the reducing agent)
What is a redox reaction?
A reaction where reduction and oxidation occur at the same time
What is a redox reaction?
A reaction where reduction and oxidation occur at the same time
What happens when chlorine water is added to potassium bromide solution
- Turns from colourless to orange
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What happens when chlorine water is added to potassium bromide solution
- Turns from colourless to orange
- Displacement reaction
- Potassium chloride and bromine is formed
What happens when chlorine water is added to potassium iodide solution?
- Turns from colourless to brown
- Displacement reaction
- Potassium chloride and iodine is formed
What happens when bromine water is added to potassium iodide solution?
- Turns from colourless to brown
- Displacement reaction
- Potassium bromide and iodide is formed
What does an acid + metal make?
Acid + metal –> salt + hydrogen
What does a metal + water make?
Metal + water –> metal hydroxide + hydrogen
What is the reactivity series?
Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Hydrogen, Copper, Silver, Gold
What is rust?
The corrosion of iron or steel when it meets oxygen (from the air) and water
- It is an oxidation reaction (the iron gains oxygen)
What is the symbol equation for rust?
iron + oxygen + water –> hydrated iron(III) oxide
What are ways to prevent rusting?
- Barrier methods
- Sacrificial method
What is the barrier method?
- Coating the iron to prevent oxygen/water reacting with it
- Plastic/coating with plastic is often used for big and small structures
- Oiling/greasing is used when moving parts are involved