Physical and Chemical Properties of Group 1 Elements Group 1 Elements: The Alkali MetalsThe elements in Group 1 are:These elements are known as alkali metals. Physical Properties of Group 1 Elements 1. Table shows some properties of Group 1 elements.Element Proton number Nucleon number Density (g cm-3) Hardness (Brinell) Melting point (°C) Boiling point … [Read more...] about Physical and Chemical Properties of Group 1 Elements