Calcium is a metal in group IIA of the periodic table with atomic number 20, an atomic weight of 40.08, and a density of 1.55 Mg/m 3. Its melting point is 838 C, and it boils at 1440 C. The electronic ...

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 ...

It is the principle strengthening element in carbon steels and low-alloy steels. Atomic number 6, atomic weight 12.01115. Manganese (Mn): Manganese is a brittle, metallic element that exists in ...

Atomic number: The number of protons in the nucleus ... Here are some popular mnemonics to help you remember the first 20 elements of the periodic table: H - Hydrogen He - Helium Li - Lithium ...

For example, the atomic number of chlorine is 17. Every chlorine atom has 17 protons and 17 electrons. It has 17 positive charges and 17 negative charges, meaning that it is neutral overall.