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 ...

14. An 18-sided shape is called an octadecagon or an octakaidecagon. 15. 18 is the atomic number for the noble gas argon. 16. Argon and the other noble gases appear in the last column, or group ...

There are 118 elements in the periodic table, each with a unique symbol and atomic number. Symbol: A one or two-letter abbreviation used to represent the element. Atomic number: The number of ...

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 ...

An element's atomic number defines it. An element with 17 protons ... So although chlorine has a mass number of 35 which means it has 18 neutrons, it can also have a mass number of 37, which ...