Everything we can see and touch, and quite a lot that we can’t as well, is made of tiny particles called atoms. Some substances, like particles of this iron, contain only one kind of atom. Iron is an ...

Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency. The valency of an element is related to how many electrons are in the outer shell.

Scientists have found the first case of an ionic crystal consisting of just one chemical element -- boron. This is the densest and hardest known phase of this element. The new phase turned out to be a ...

Students learn to classify matter as elements, compounds, and mixtures. Matter: Classification of Matter: Students learn to classify matter as elements, compounds, and mixtures and to distinguish ...