Question

How to determine the amount of protons, electrons, and neutrons in an atom?

Answer 1

Answer

The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules.

1. The number of protons in the nucleus of the atom is equal to the atomic number (Z).
2. The number of electrons in a neutral atom is equal to the number of protons.
3. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
4. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).

Examples: Let's determine the number of protons, neutrons, and electrons in the following isotopes.

12C   13C   14C   14N  

The different isotopes of an element are identified by writing the mass number of the atom in the upper left corner of the symbol for the element. 12C, 13C, and 14C are isotopes of carbon (Z = 6) and therefore contain six protons. If the atoms are neutral, they also must contain six electrons. The only difference between these isotopes is the number of neutrons in the nucleus.

12C: 6 electrons, 6 protons, and 6 neutrons

13C: 6 electrons, 6 protons, and 7 neutrons

14C: 6 electrons, 6 protons, and 8 neutrons

Answer 2

The amount of protons, electrons, and neutrons in an atom can be determined by its Atomic number(Z) and Mass number(M).

• The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules.
• The number of protons in the nucleus of the atom is equal to the atomic number (Z).
• The number of electrons in a neutral atom is equal to the number of protons.
• The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
• The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).