Physical Properties
Specification Point 5.1 C:
Recall that most metals are transition metals and that their typical properties include:
a) high melting point
b) high density
c) the formation of coloured compounds
d) catalytic activity of the metals and their compounds as exemplified by iron
- Most of the known metals are transition metals, which have all of the typical properties of metals.
- They are very hard and strong and are good conductors of heat and electricity.
- They are highly dense metals and have very high melting points:
- Titanium melts at 1,688ºC whereas potassium melts at only 63.5ºC, not far off the average cup of tea!
- Transition metals can have more than one oxidation state as they can lose a different number of electrons, depending on the chemical environment they are in:
- Chromium forms up to three ions with different charges: Cr2+, Cr3+ and Cr6+.
The transition elements on the Periodic table
- Compounds containing transition elements in different oxidation states will have different properties and colours.
- Transition metals are often used as catalysts.
- These are substances which speed up the rate of a reaction without being used up in the process as they do not chemically participate in the process.
- Common transition metal catalysts include:
- Iron which is used in the Haber Process.
- Vanadium pentoxide (V2O5) is used in the Contact Process to produce sulfuric acid.
The colours produced by ions of the transition elements
Corrosion of Metals
Specification Point 5.2C:
Recall that the oxidation of metals results in corrosion.
- Corrosion is the destruction of materials by chemical substances in their environment which act on them over a period of time.
- Most metals can corrode in the presence of oxygen to form the corresponding metal oxide.
- Corrosion is caused by redox reactions:
- The metal loses electrons and is oxidised while the oxygen gains electrons and is reduced.
- Rusting is the name given specifically to the corrosion of iron in the presence of water and oxygen from the air.
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Author: Morgan
Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.
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