No. The mass also includes electrons.
The sum of all protons and neutrons - Apex Learning
The sum of all Protons and Neutrons.
Mass number = Protons+Neutrons
The sum of protons and neutrons in an atom is called mass number.
Mass number!:)
The sum of protons and neutrons is the atomic mass.
The mass number of an atom is the sum of the protons and neutrons in its nucleus. Therefore, for an atom of calcium with 20 protons and 20 neutrons, the mass number would be 40.
The mass number
Atomic mass number of the atom. The best way to remember it is: the majority of the mass of an atom is made up of the protons and neutrons (the electrons are very light!), therefore the atomic mass number is the sum of the protons and neutrons.
The atomic mass of an atom is the total mass of protons, neutrons, and electrons in the atom, measured in atomic mass units (amu). It is approximately equal to the sum of the number of protons and neutrons in the atom's nucleus.
Sum of protons and neutrons is the Mass number of the element. The number of protons is equal to the number of electrons. Neutrons and protons are sub atomic particles.
By the sum of protons and neutrons we obtain the mass number of the atom which is written at the top of the atom periodic number. We can also obtain the mass number by adding the atomic number and the number of neutrons because the atomic number and the number of protons are same. You know that scientists have discovered some particles which are smaller than protons and neutrons and these are known as quartz.