The Modern Periodic Table

There are 100ish elements, which all materials are made of
In the periodic table the elements are laid out in order of increasing atomic, proton, number. Arranging the elements like this means there are repeating patterns in the properties of the elements. (The properties are said to occur periodically, hence the name periodic table)
If it wasn’t for the periodic table organising everything, you’d have a heck of a job remembering all those properties.
It’s a handy tool for working out which elements are metals and which are non-metals. Metals are found to the left and non-metals to the right

Elements with similar properties form columns
These vertical columns are called groups
The group number tells you how many electrons there are in the outer shell.
- For example, Group 1 elements all have one electron in their outer shell and Group 7 all have seven electrons in their outer shell.
- The exception to the rule is Group 0, for example Helium has two electrons in its outer shell. This is useful as the way atoms react depends upon the number of of electrons in their outer shell, so all elements in the same group are likely to react in a similar way
If you know the properties of one elements, you can predict properties of other elements in that group. For example, the Group 1 elements are Li, Na, K, Rb, Cs and Fr. They’re all metals and they react in similar ways
You can also make predictions about trends in reactivity
- e.g. In Group 1, the elements react more vigorously as you go down the group, but in Group 7 reactivity decreases as you go down the group
The rows are called periods. Each period represents another full shell of electrons

Note

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