Mass
To find the number of neutrons in an atom, you would subtract the atomic number (number of protons) from the atomic mass (sum of protons and neutrons). The difference between the atomic mass and the atomic number gives you the number of neutrons in the atom.
The atomic number of an element is defined by the number of protons in its nucleus. Therefore, protons equal the atomic number, while neutrons do not; instead, the number of neutrons can vary among isotopes of the same element. The atomic number determines the element's identity, whereas the total number of nucleons (protons and neutrons) gives the atomic mass.
The element that has 8 protons and 8 neutrons is oxygen.
In an atom of ^11B5, there are 5 protons and 6 neutrons. This is because the atomic number (5) specifies the number of protons, and the atomic mass (11) minus the atomic number gives the number of neutrons.
Atomic mass is protons + neutrons, and the atomic number (4) gives you the number of protons. Thus, this atom would have 5 neutrons.
You get the number of neutrons in the atom. The mass number represents the total number of protons and neutrons in the nucleus, while the atomic number represents the number of protons. Subtracting the atomic number from the mass number gives you the number of neutrons because the difference accounts for the protons.
It gives the number of nucleons = protons + neutrons.
An atom with an atomic number of 82 has 82 protons. The mass number of 112.6 represents the total number of protons and neutrons in the nucleus, so subtracting the atomic number of protons gives the number of neutrons: (112.6 - 82 = 30.6) neutrons.
Mg has 12 protons since it is element number 12 on the periodic table. To calculate the number of neutrons, subtract the atomic number (12 protons) from the atomic mass (26), which gives 14 neutrons in this case.
The number of protons plus the number of neutrons in an atom gives the atomic mass number. This total reflects the combined mass of the nucleus of an atom, as protons and neutrons contribute significantly to its mass. The atomic mass number is often used to distinguish between different isotopes of an element.
The atomic mass number of an isotope is the sum of the number of protons and neutrons in the nucleus. In this case, atomic number 5 represents the number of protons, and adding the 6 neutrons gives an atomic mass number of 11 for this particular isotope.
8. Mass number is the number of neutrons plus the number of protons. The number of protons gives the atomic number.