CHEMISTRY Lead(Pb)係響Group IV但點解佢係2+

Lead takes on two different oxidation states, like tin, the +2 and the +4 oxidation states. Unlike the rest of the group, where the +4 is the more common and the most stable due to having a valency of 4, lead is more stable in its Pb(II) form. This is a result of the 'inert pair effect'. This describes the observation for group 13 and 14 elements, where the oxidation state is seen to be 2 below the expected group valency. The heavier elements in the group require less energy compensation when forming bonds, therefore 2 of the 4 electrons become less available for bonding down the group and the lower valence state is favoured. The effect is best regarded as a reminder of the trend rather than an explanation.
The compounds that it forms when in its +4 oxidation state are found to be good oxidizing agents.