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 combined number of protons and neutrons is known as the mass number of an atom. It can be used to calculate the atomic mass by adding the total number of protons and neutrons in the nucleus of an atom.
The number of protons in a nucleus of an atom is called the "proton number", strangely enough. If you are a physicist, you will most likely prefer this term. Chemists however, would rather call it "atomic number".
Atoms of the same element cannot have different numbers of protons. Different numbers of protons mean different elements. An atom with the a different number of neutrons is called an isotope.
The mass number is the sum of protons + neutrons.
25 is the number of protons and neutrons added together. The atomic number of Mg is 12 which is the number of protons. So 25 - 12 = 13 neutrons.
mass number = protons + nuetrons
The sum of protons and neutrons in an atom is called mass number.
Atoms which have different number of protons and neutrons but have the same molecular weight are called Isobars.
mass number = protons + nuetrons
An atom that has more neutrons than protons is called an Isotope.
Carbon Number of Protons/Electrons: 6 Number of Neutrons: 6
The atomic mass
The atomic mass of an atom is determined by the sum of the number of protons and neutrons in its nucleus. Protons have a positive charge, and neutrons have no charge. The total number of protons and neutrons in an atom's nucleus is called its mass number.
The combined number of protons and neutrons is known as the mass number of an atom. It can be used to calculate the atomic mass by adding the total number of protons and neutrons in the nucleus of an atom.
The number of protons in a nucleus of an atom is called the "proton number", strangely enough. If you are a physicist, you will most likely prefer this term. Chemists however, would rather call it "atomic number".
Two atoms with the same number of protons but different numbers of neutrons are called "isotopes".
Mass number