What is unique about each element of the periodic table?
The periodic table is based on a number of protons in the nucleus.
In the beginning, when the periodic table wasn't discovered totally, many scientists tried to make columns of the different atoms. Most of these lists were based on the reactivity of the elements.
The current periodic table has many awesome featured in it! From the top left to the bottom right the elements are sorted by the number of protons in the nucleus (this is how different elements are defined).
In the image below, we see different coloured blocks, which represents elements with similar properties.
Back in the time, they could even suggest properties of elements that weren't even made yet!
So the unique thing about every element it a number of protons in the nucleus, which will cause the element to behave in a certain way.