Iron may be extracted from iron (II) sulfide, FeS.
Iron (II) sulfide, FeS , is ionically bonded.
Suggest why chemists find it convenient to classify bonding into ionic, covalent and metallic.
allows them to explain the properties of different compounds/substances OR enables them to generalise about substances
OR enables them to make predictions
Marking guidance:
Accept other valid answers.
Explain why the addition of small amounts of carbon to iron makes the metal harder.
disrupts the regular arrangement «of iron atoms/ions»
OR
carbon different size «to iron atoms/ions»
prevents layers/atoms sliding over each other
Iron(II) sulfide can be produced by heating powdered iron and sulfur together.
Outline why solid iron(II) sulfide is a polar covalent compound. Use sections 9 and 17 of the data booklet.
<<electronegativity difference>> ΔX=0.8 AND average
<<electronegativity >> X = 2.2
Titanium is a transition metal.
Explain why an aluminium-titanium alloy is harder than pure aluminium.
titanium atoms/ions distort the regular arrangement of atoms/ions OR titanium atoms/ions are a different size to aluminium «atoms/ions» prevent layers sliding over each other
Marking guidance:
Accept diagram showing different sizes of atoms/ions.