Calcium Atomic Structure. Number of Energy Levels: 4. First Energy Level: 2. Second Energy Level: 8. Third Energy Level: 8. Fourth Energy Level: 2. Calcium · Elements by Name · Elements by Number · Home. Graphic courtesy of ChemicalElements.com. read more
If we look at the symbol for calcium in the periodic table we can see that it has an atomic number of 20 and a mass number of 40. The atomic number is always equal to the number of protons in the nucleus and the number of electrons (in an atom, not an ion) orbiting the nucleus. read more