LIFE SCIENCE

Detailed explanation-1: -How many protons are in an atom with an atomic number of 20, an atomic mass of 45, and a charge of +2? answer choices. 20.

Detailed explanation-2: -Hence, symbol=Ca+2, atomic number = number of protons = 20, number of electrons = 18, mass number = 40.

Detailed explanation-3: -For example, calcium (Ca) has an atomic number of 20. This means that all calcium atoms contain 20 protons. A neutral atom of calcium will also have 20 electrons.

Detailed explanation-4: -The atomic symbol of the element shows that the element is calcium and that it has 20 protons in its nucleus. The atomic symbol also shows that the sum of the number of protons and the number of neutrons in the nucleus is 41.