This video is an interactive lesson in calculating an atom’s mass and atomic number. Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells. The numbers of ...

according to increasing atomic number. Scientists use the periodic table to quickly refer to information about an element, like atomic mass and chemical symbol. The periodic table’s arrangement also ...

It is a graphic formulation of the periodic law, which states that the properties of the chemical elements exhibit a periodic dependence on their atomic numbers ... mass. Because not all elements were ...

The Periodic Table of Elements. Each entry contains the atomic number, chemical symbol, and atomic mass to two decimal places on elements where data is available. Undefined cells contain a space. Row ...