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Calcium is dull gray, but it is shiny when scratched. Other physical properties. Calcium is an excellent conductor of electricity. It is very soft and easily scratched. Chemical properties. Calcium reacts rapidly with air to form a coating of gray oxide, and it burns with a red flame.
Quick Answer. Calcium is a metallic element that has the atomic number 20. Some of its most important chemical properties are that it has 10 isotopes, an atomic mass of 50.08 grams per mole and a melting point of 840 degrees Celsius. Physically, calcium is a solid at room temperature, is slightly softer than aluminum and is silver-white color.