AP BIOLOGY

Detailed explanation-1: -The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).

Detailed explanation-2: -Both protons and neutrons have a mass of 1, while electrons have almost no mass. The element hydrogen has the simplest atoms, each with just one proton and one electron. The proton forms the nucleus, while the electron orbits around it.

Detailed explanation-3: -The atomic number is the number of protons in an element, while the mass number is the number of protons plus the number of neutrons.

Detailed explanation-4: -The mass number tells us the nucleus contains 19 particles in total. Since 9 of these are protons, the other 10 are neutrons. We call it the mass number because virtually all the mass in an atom comes from the protons and neutrons-electrons weigh about 1/2000th of the mass of a proton or neutron.

Detailed explanation-5: -proton, stable subatomic particle that has a positive charge equal in magnitude to a unit of electron charge and a rest mass of 1.67262 × 10−27 kg, which is 1, 836 times the mass of an electron.