The mass of the atom is determined by
the total number of protons and neutrons in the nucleus.
The mass of an atom is primarily determined by the sum of the masses of its protons and neutrons. Protons and neutrons both have a mass of approximately 1 atomic mass unit (amu). Electrons, which orbit the nucleus, have a much smaller mass and therefore do not significantly contribute to the total mass of an atom. Therefore, the mass number of an element is determined by the sum of the number of protons and neutrons in its nucleus.
The mass of an atom is determined by the combined mass of its protons and neutrons, which are found in the nucleus of the atom. Protons carry a positive charge and have a mass of approximately 1 atomic mass unit (amu), while neutrons carry no charge and also have a mass of approximately 1 amu. Electrons, which are negatively charged particles found in the electron cloud surrounding the nucleus, have a much smaller mass, approximately 1/1836 amu. However, their mass is generally not considered when calculating the mass of an atom because it is significantly smaller compared to the mass of protons and neutrons. Therefore, the mass of an atom is primarily determined by the sum of its protons and neutrons.
The mass of an atom is determined by the combined mass of its protons, neutrons, and electrons.
To determine the mass of an atom, you need to know the number of protons and neutrons in its nucleus. The mass of a proton is approximately 1 atomic mass unit (amu), and the mass of a neutron is also approximately 1 amu. The number of protons in an atom is equal to its atomic number, which is listed on the periodic table.
Next, you need to determine the number of neutrons in the nucleus. This can be calculated by subtracting the atomic number from the atomic mass number. The atomic mass number represents the total number of protons and neutrons in the atom.
The mass of an electron is much smaller compared to protons and neutrons, so it can be ignored when calculating the mass of an atom.
Once you have the number of protons and neutrons, you simply add them together to get the total mass of the atom.
For example, let's take the element carbon. Carbon has 6 protons, so its atomic number is 6. The atomic mass number for carbon is 12.01 amu. To find the number of neutrons, subtract the atomic number from the atomic mass number: 12.01 - 6 = 6.01 neutrons. Therefore, the mass of a carbon atom is approximately 12 amu (protons) + 6.01 amu (neutrons) = 18.01 amu.
In summary, the mass of an atom is determined by the total number of protons and neutrons in its nucleus.