Answer:
The total number of protons and neutrons in an atom is known as the mass number. It represents the sum of the protons and neutrons present in the nucleus of an atom. The mass number is denoted by the letter A.
Protons are positively charged particles found in the nucleus of an atom, while neutrons are neutral particles also located in the nucleus. Electrons, which are negatively charged particles, orbit around the nucleus in specific energy levels or shells.
The mass number is an important characteristic of an atom as it determines its atomic mass. Atomic mass is calculated by adding up the masses of protons and neutrons in an atom. The atomic mass is expressed in atomic mass units (amu) or unified atomic mass units (u).
To determine the total number of protons and neutrons in an atom, you can use the following formula:
Mass Number (A) = Number of Protons (Z) + Number of Neutrons (N)
Where Z represents the atomic number, which corresponds to the number of protons in an atom. The atomic number determines the element's identity. N represents the number of neutrons, which can vary within atoms of the same element, resulting in different isotopes.
It is important to note that while the mass number represents the total number of protons and neutrons, it does not include electrons. Electrons have a negligible mass compared to protons and neutrons, so they are not considered when calculating the mass number.
In summary, the total number of protons and neutrons in an atom is represented by its mass number (A), which is obtained by adding up the number of protons (Z) and neutrons (N) present in the nucleus.
Step-by-step explanation: