Chemistry - Redox properties and metallic/non-metallic character
Redox properties and metallic/non-metallic character
Trends in electron attraction, electron loss and electron gain tie in very
nicely with redox properties, which in turn link in nicely with metallic
and non-metallic character.
Put simply, the metals on the left of the periodic table tend to lose
electrons in chemical reactions, i.e. they are usually oxidised.
In giving up electrons to another species, a metal causes that other
species to be reduced. The metals at the start of period 3, for example,
act as reductants.
Conversely, the ability of non-metals such as Cl on the right of the
periodic table to accept electrons means that they cause other species to
give up electrons, i.e. they oxidise these other species.
In other words, the non-metals to the right of a period act as oxidants.
This is consistent with the trend that metallic character decreases and
non-metallic character increases across a period.
Consider the trends going down a group. The fact that potassium, which is
further down group I than sodium, is more reactive than sodium means that
potassium atoms give up their one valence electron more readily than do
This is also consistent with decreasing electronegativity going down a
Given that losing valence electrons is a distinct characteristic of metals
and reductants, it follows that metallic character and reducing strength
increase going down a group. The corollary of this is that non-metallic
character and oxidising strength decrease going down a group.
Previous | Next