Group IV

Carbon Silicon Germanium Tin Lead
C Si Ge Sn Pb

Carbon is a non-metal. It exists as several different allotropes. Soot, graphite and diamonds are all composed of the same kind of atom ie carbon. The difference in their properties is because the atoms are bonded in different ways. In graphite, the atoms of carbon are arranged into sheets. Graphite can be used as a lubricant. In diamonds, the atoms of carbon are bonded together into a three dimensional solid. This makes diamond a very hard substance.

Silicon is a non-metal. It is used in the manufacture of silicon chips. A very large crystal of silicon can be used to make a chip by adding a small amount of another element.

Germanium is a ……. ? Wel it has the some properties of both metals and non-metals

Tin is a metal. Tin can were always made of iron with a thin coating of tin to stop them rusting.

Lead is a metal.


Electrons have a very tiny mass: they don’t have “Zero Mass” as it says in the animation. However, you don’t need to take account of their mass when you are calculating molecular weights: for your purposes, the atomic mass is calculated by adding the number of neutrons to the number of protons.

Since electrons do actually have some mass, they cannot travel at the speed of light. They would need an infinite amount of energy to travel this fast. However, they do buzz around the atomic nucleus at very fast speeds.

When an atom is excited, ie. it has too much energy, electrons can escape from their normal orbits into higher energy orbits or escape the atom completely; this would leave the atom in an ionised state.

The animation shows electron pairs: since electrons have negative charges, they repel each other so they would normally be at opposite ends of their orbit.