C4 - The Periodic Table Flashcards
What is the plum pudding model?
There is a positively charged ‘pudding’ with negative electrons inside
How was the plum pudding model proved wrong?
They used a thin piece of gold and fired particles through it and most went through but some deflected backwards showing a positive nucleus
What is Bohr’s model?
There is a nucleus with fixed orbit shells with electrons on these
What is the nucleus?
- Contains protons and neutrons
- It has a positive charge
What are the electrons?
- Negatively charges
- Move around on the shells
- They have virtually no mass
What is the mass and charge of protons, neutrons and electrons?
Mass Charge
Proton. 1. 1
Neutron. 1. 0
Electron. 0.0005. -1
What is the mass number?
Total number of protons and neutrons (big number)
What is the atomic number?
Number of protons (small number)
What are isotopes?
They are the same except from have extra neutrons
Same atomic number but different mass number
What did Döbereiner make the periodic table look like?
He ordered them in relative atomic mass
What did Newland make the periodic table look like?
He put it in similar properties such as metals non metals…
What did Dmitri Mendeleev’s periodic table look like?
He put them in order of atomic mass and similar properties but left gaps for predicted elements
What do the periods in the periodic table represent?
The number of shells
What do the groups of the periodic table represent?
This shows the number of electrons on the outer shell
What is ionic bonding?
This is where a metal and a non metal transfers electrons
What is covalent bonding?
When two non metals share electrons
What happens as you go down group 1 metals?
They get more reactive as the outer electron is more easily lost
What are group 1 metals?
Alkali metals
What is oxidation and reduction?
O xidation
I s
L oss
R eduction
I s
G ain
What happens when group 1 metals react with water?
Hydrogen gas is produces meaning it fizzes, moves very fast, bubbles and sometimes ignites
What flame is produced with lithium, sodium and potassium?
Lithium = red flame Sodium = yellow/orange flame Potassium = lilac flame
What are group 7 metals?
Halogens
What happens as you go down the group 7 metals?
As you go down they get less reactive because it’s harder to gain an electron
What happens when halogens are reacted?
They form salts
What happens with more and less reactive halogens?
The more reactive ones will displace the less reactive ones
What are some of the useful properties of metals?
They have a crystal structure:
- High mp and bp
- Strong
- Good conductors
What are super conductors?
Metals at very low temperatures so they loose there resistance
What are super conductors used for?
- Power cables
- Electromagnets
- Electronic circuits
What are transition metals?
Similar to normal metals but make good catalysts
Give examples of transition metals which are catalysts.
Iron (harber process)
Nickel (margarine)
What is thermal decomposition?
This is the breaking down with heat
What is an example of thermal decomposition using copper(II) carbonate?
Copper(II) carbonate > copper oxide + carbon dioxide
CuCO(3) > CuO + CO(2)
What is a precipitation reaction?
This is when two solutions react and form an insoluble solid in the solution
What is the precipitation reaction between copper(II) sulfate + sodium hydroxide?
Copper(II) sulfate + sodium hydroxide > copper(II) hydroxide + Sodium sulfate
What colours are made with transition metals?
Copper(II) hydroxide = blue
Iron(II) hydroxide = grey/green
Iron(III) hydroxide = orange/brown
How do we get our water?
- Surface water
- Groundwater
What are the four steps in water purification?
- Mesh
- Sand filtration (removes the large materials in it)
- Sedimentation (makes fine particles clump together when iron sulphate is added)
- Chlorination (kills microbes)
What impurities are in tap water?
- Nitrate residue
- Lead compounds
- Pesticide residue
What can you test water for?
Dissolved ions
How do you test for sulfate ions?
Use barium chloride
How do you test for sulfate ions using barium chloride?
1) Add hydrochloric acid to the test sample
2) Add ten drops of barium chloride solution
3) If there is a white precipitate then its present
How do you test for halide ions?
Use silver nitrates
How do you test for halide ions using silver nitrate?
1) Add some dilute nitric acid to the test sample
2) Add 10 drops of silver nitrate solution
3) If halide ions are present a precipitate will be formed
What do different coloured precipitates show when testing for halide ions?
- Chloride ions = white precipitate
- Bromide ions = cream precipitate
- Iodide ions = pale yellow precipitate
