Argon is an inert gas in group VIII A of the periodic table with atomic number 18, an atomic weight of 39.948, and a density of 1.40 Mg/m 3. In the solid state it forms an fcc crystal with a melting ...

The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

Atomic Number and Mass Number of Elements: Atoms are the building blocks of matter. They are responsible for the format of all living and non-living things. Understanding their molecular structure ...

Atomic structure - AQA Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells. The number of subatomic particles in an atom can be calculated from the atom's ...

The numbers of subatomic particles in an atom can be calculated from its atomic number and mass number. The periodic table - AQA Mendeleev made an early periodic table. In the modern periodic ...