Hi and welcome back to freesizelessons.co.uk. By the end of this video you should be able to describe the properties of transition elements in comparison with the alkali metals. You should then be able to describe the reactivity of transition elements.
Remember that we find metals on the left hand side of the periodic table and non-metals on the right hand side. The transition elements are found in the central part of the periodic table and these are all metals. So we're going to start by recapping the metals that we've already looked at, those in group one which we call the alkali metals.
The alkali metals are soft and they can be cut with a knife. They also have relatively low melting points. The alkali metals are low density.
In fact the first three alkali metals which are lithium, sodium and potassium are less dense than water. The alkali metals all react very rapidly with oxygen, chlorine and water and we saw those reactions in the video on the alkali metals. And finally all the alkali metals form one positive ions.
For example sodium forms the ion Na+. So in this video we're going to look at the transition elements and we're going to compare them with the alkali metals in group one. The first key property is that transition elements are hard and strong metals.
A good example is iron. Transition elements all have high melting points so they don't melt easily. The only exception is mercury which is a liquid at room temperature.
Transition elements all have a high density. Transition elements are much less reactive than group 1 metals, for example with oxygen, chlorine and water. And unlike group 1 metals, transition elements can form ions with different charges. So we can see iron forming a 2 plus, and a 3 plus ion, and nickel forming a 2 plus and a 4 plus ion.
Transition elements form coloured compounds and that's really important. So I'm showing you iron oxide which is a reddish colour, manganese chloride which is pink, and chromium chloride which is purple. Finally the transition elements can be used as catalysts and we'll see several examples of that in later videos.
You'll find plenty of questions on the transition elements in my revision workbook, which you can get by clicking on the link above. Okay, so hopefully now you should be able to describe the properties of transition elements in comparison with the alkali metals. You should then be able to describe the reactivity of transition elements.