How many protons; neutrons and electrons are there in a neutral atom of the isotope of chlorine named chlorine-37?
The correct answer and explanation is:
A neutral atom of the isotope chlorine-37 contains:
- Protons: 17
- Neutrons: 20
- Electrons: 17
Explanation
The element chlorine (Cl) has an atomic number of 17. The atomic number indicates the number of protons in the nucleus of the atom. Since chlorine always has 17 protons, this number does not change between isotopes.
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. The isotope name “chlorine-37” tells us the mass number of the isotope, which is 37. The mass number is the total number of protons and neutrons in the nucleus.
To find the number of neutrons, subtract the atomic number from the mass number:
Number of neutrons = Mass number – Atomic number = 37 – 17 = 20 neutrons.
For a neutral atom, the number of electrons is equal to the number of protons. This balances the positive charge of the protons with the negative charge of the electrons, making the overall charge zero.
Therefore, in a neutral chlorine-37 atom:
- Protons = 17 (from atomic number)
- Neutrons = 20 (37 – 17)
- Electrons = 17 (equal to protons in neutral atom)
Understanding these values is important because the number of protons defines the element, the number of neutrons determines the isotope, and the number of electrons affects the atom’s charge and chemical behavior. Chlorine-37 is one of the two stable isotopes of chlorine, the other being chlorine-35. The difference in neutrons causes a slight difference in atomic mass but does not change the chemical properties significantly.