• Question: What metals do you add to make the blue beads?

    Asked by lunaliu to Rowena on 12 Mar 2014.
    • Photo: Rowena Fletcher-Wood

      Rowena Fletcher-Wood answered on 12 Mar 2014:

      Copper! Have you seen the green or blue tinted glasses used in modern buildings? Green is iron and the much fresher, prettier blue is copper. The different colours arise because free electrons jump abput between unoccupied d orbitals. Light is absorbed to power these jumps and the light that isn’t absorbed gives us the colours we see.

Comments

  • Photo: jgb404

    jgb404 commented on :

    Would copper not make green?

  • gedwards13 commented on :

    Great question ‘lunaliu’!

  • Photo: Rowena

    Rowena commented on :

    It depends not only on the metal, but on the charge on the metal. Some charges are more stable than others and when you heat them up in air they make the most stable one. Copper +2 is most stable and this is blue, whilst iron +3 is most stable for iron and this is yellow/brown and iron +2 green.

    Colour depends upon energy levels the electrons sit in – “shells”. These change depending on charge and shape. Because the charge in the middle, the nucleus, is different element to element, the energy levels are always a bit different element to element. Free electrons jump between energy levels by absorbing light to give the colour. So this is how we get different colour from different metals with free electrons!