Brittle and a poor conductor of heat andelectricity. Carbon, sulphur and iodine are examples of non-metals. The Periodic Table classified elements into groups based on their common properties. To recall, there are eight groups of elements and we are going to look at the properties of elements in Group 1, 7, 0 and also transition elements, the biggest group of elements that lie between Group 2 and Group 3 in the Periodic table.