The periodic table
Learn about the particle model.
This lesson includes:
- two videos showing a metal and non-metal in use
- two activities
In 1867 scientist Dmitri Mendeleev realised that many of the elements shared similar chemical properties. This led him to group similar elements together and produce a visual representation of this, he called the periodic table.
In the periodic table the elements are arranged in order of increasing atomic number (or number of protons in the nucleus) from left to right, beginning with hydrogen (H) which has just one electron surrounding its nucleus.
- the horizontal rows are called periods
- the vertical columns are called groups
The groups are numbered 1-7 (left to right). Group 8 (or 0) is the furthest right group and contains the noble gases.
Elements in the same group have similar chemical properties to each other and will often show particular patterns. For example, as you go down group 1 the reactivity of the element increases, but the melting point decreases.
Metals and non-metals
Every element is either a metal or a non-metal. All metals are situated on the left hand side of the periodic table and all the non-metals are on the right. You can see the grey zig-zag that separates them in the periodic table above.
The central part of the periodic table between groups 2 and 3 contains the transition metals.
Iron, magnesium and gold are examples of metal elements. All metals have three common properties:
- they are shiny, especially when they are freshly cut
- they are good conductors of heat and electricity
- they are malleable (they can be bent and shaped without breaking)
Oxygen, carbon, sulphur and chlorine are examples of non-metal elements. Compared to metals, non-metals tend to be:
- dull (not shiny)
- poor conductors of heat and electricity (they are insulators)
- weak and brittle (they easily break or shatter when solid)
There are lots of ways to try out your science skills.
There's more to learn
Have a look at these other resources around the BBC and the web.