Because your Teeth are composed of calcium, phosphorus, and other minerals. ... But bones are still not as strong as teeth. The hardest part of the human body ,teeth mostly consist of a calcified tissue called dentine. The tooth's dentine tissue is covered in enamel, that hard, shiny layer that you brush.
Elements in the same group have the same amount of electrons.
Elements in the same period have the same amount of atomic orbits.
Hope this helps!
