• Question: what is the purpose of a periodic table

    Asked by kirstyloo to Douglas, Matt, Tom on 24 Jun 2010 in Categories: .
    • Photo: Douglas Blane

      Douglas Blane answered on 24 Jun 2010:

      It shows you all the elements we know. It also arranges them in groups that have the same kind of chemistry.

      Have a look here for instance http://www.webelements.com/

      I like this one because you can click on any element and find out more. There’s also a little audio for each element, so you can hear as well as read about it.

      So take a look at group 1 in this table. You have hydrogen, lithium, sodium, potassium etc. These are metals that form positive ions.

      Way over on the right you have group 18, containing helium, neon, argon etc. These are the noble gases. They don’t combine with anything because they all have a complete outer electron shell.

      Next left is group 17, with fluorine, chlorine, bromine etc. These form negative ions.

      They react ferociously with the elements in group 1.

      You can tell loads from a periodic table especially an online one like this.