KS3 Science Revision

The periodic table is a table containing elements. It is organised into rows called groups and columns called periods. The elements are arranged based on their atomic and mass numbers. The modern periodic table was written be Mendeleev. Many people had tried to put the elements into order, all with some success. But Mendeleev arranged them perfectly with no errors. When designing his first draft, he left gaps for elements that had not yet been discovered. These gaps meant that everything could allign perfectly. He arranged similar elements vertically.