The Periodic Table is a well-organized chart that contains all 118 known elements in the universe. These elements are the ...

We call these letters symbols. And an element is a pure substance made from only one type of atom. And there are quite a lot of elements. There are something like 100, and each has a unique symbol ...

This symbol shows that chlorine has 35 particles ... as the number of electrons and protons are equal in a neutral atom, chlorine also has 17 electrons. The relative mass of a nucleus is the ...