Unit 3. Properties of transition metals

Question 1

Properties of transition metals

Answer 1

Properties
Most of the known metals are transition metals and they have typical properties of metals
They are very lustrous, they are hard, strong and are good conductors of heat and electricity
They are highly dense metals and have very high melting points
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
The melting point, density and common ions of the elements Cr, Mn, Fe, Co, Ni and Cu are shown below

Question 2

Uses of transition metals

Answer 2

Catalysts
The transition elements are used extensively as catalysts which are substances that speed up the rate of a reaction without being used up in the process
They do not take part in the reaction
Their catalytic characteristics stem from their ability to interchange between a range of oxidation states
This allows them to form complexes with reagents which can easily donate and accept electrons from other chemical species within a reaction system
Common transition metal catalysts include:
Iron which is used in the Haber Process
Vanadium pentoxide (V2O5) which is used in the Contact Process to produce sulfuric acid
Nickel which is used in the hydrogenation of alkenes

Question 3

Differences between Group 1 metals & transition metals

Answer 3

The transition elements are located between Groups 2 and 3 in the centre of the periodic table
They have all of the typical properties of metals but there are some key differences between them and the Group 1 metals
Location of the transition metals in the Periodic Table
Transition metals in Periodic Table, IGCSE & GCSE Chemistry revision notes

The transition elements on the Periodic table

All of the Group 1 metals form ions with a +1 charge while the transition metals can form ions with variable charges
For example iron can form an Fe2+ ion or an Fe3+ ion
The transition metals are much harder, stronger and denser than the group 1 metals, which are very soft and light
They have much higher melting points e.g. titanium melts at 1,688 ºC whereas potassium melts at only 63.5 ºC, not far off the average cup of tea!
The transition metals are much less reactive than the Group 1 metals
The alkali metals react with water, oxygen and halogens while the transition metals either react very slowly or do not react at all
A classic example of this is the reaction with oxygen
A Group 1 metal will tarnish in the presence of oxygen as a metal oxide is formed
When cut with a knife, the shiny appearance of the metal disappears in seconds as it is covered by the dull metal oxide
Iron on the other hand can take several weeks to react with oxygen to form iron oxide (rust) and requires the presence of water