12
The isotope 12C has the mass number 12.
Carbon has a mass number of 12.
The mass number is the sum of protons and neutrons in an atom. Since magnesium has 12 protons, a magnesium atom with 14 neutrons would have a mass number of 26 (12 protons + 14 neutrons = 26 mass number).
A magnesium atom with a mass number of 24 has 12 protons because the atomic number of magnesium is 12. To find the number of neutrons, you subtract the atomic number from the mass number: 24 (mass number) - 12 (atomic number) = 12 neutrons.
The mass number of a carbon atom is 12. This number represents the total number of protons and neutrons in the nucleus of the carbon atom.
Carbon is a non metal element. Mass number of it is 12.
Number of neutrons = Mass number - Atomic number = 22 - 12 = 10
The atomic number of magnesium is 12. Its nucleus must contain 12 protons and no electrons. The atomic number of an atom is determined by the number of protons. Electrons are not in the nucleus.
To find the number of neutrons in carbon-12, you subtract the atomic number from the mass number. Carbon has an atomic number of 6, which means it has 6 protons. Since carbon-12 has a mass number of 12, the number of neutrons is 12 (mass number) - 6 (atomic number) = 6 neutrons.
12. When a nuclide is (properly) named in the form [element name]-[number], the number is always the mass number.
The element with a mass number of 12 is carbon. Carbon has an atomic number of 6.
Sodium is a metal element. Mass number of it is 23.