Mass number!:)
The mass number is the sum of protons + neutrons.
An atom with 55 protons is a cesium atom. The mass number is the sum of the numbers of protons and neutrons, in this instance 131. Therefore, the atom is Cs-131.
20. the mass of an atom is determined by the sum of the number of neutrons and protons the atom has.
The number protons in an atom is called the atomic number (it is this number that tells us which element the atom is). The number of neutrons in an atom can change, but the term for the amount of neutrons is called an isotope. The number of protons and neutrons added together is called the atomic mass.
The mass number of an atom of calcium with twenty protons and twenty neutrons is 40. This is because the mass number is the sum of the protons and neutrons in the nucleus of an atom.
Mass number = Protons+Neutrons
The sum of all Protons and Neutrons.
The sum of the number of protons and neutrons in an atom
The sum of protons and neutrons in an atom is called mass number.
protons and neutrons in an atom. It is the sum of protons and neutrons in the nucleus of an atom.
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 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.
atomic number
The sum of the number of the protons and neutrons in the nucleus of an atom is called as atomic mass.
The mass number is the sum of protons + neutrons.
The mass number of this atom is 23, the sum of the number of protons and neutrons.