It is the principle strengthening element in carbon steels and low-alloy steels. Atomic number 6, atomic weight 12.01115. Manganese (Mn): Manganese is a brittle, metallic element that exists in ...

Hydrogen is a non-metal, but it is often put in the middle. Notice that most elements are metals, rather than non-metals. The only liquid elements at room temperature are bromine (Br) and mercury ...