Consider an atom with 6 protons, 6 neutrons, and 6 electrons. state the number of protons, neutrons, and electrons that would occur in a different isotope of the same element, and explain what changed by relating the change to the definition of an isotope.

Explanation:

An isotope is defined as the specie which contains same number of protons but different number of neutrons.  

For example, and are isotopes.

In a neutral carbon atom, there are 6 protons and 6 neutrons.

As it is known that in a neutral atom the number of protons equal to the number of electrons.

This means that in a neutral carbon atom there are also 6 electrons.

Whereas is an isotope of carbon atom whose atomic number is 6 and atomic mass is 13.

Hence, calculate the number of neutrons in as follows.

                   Atomic mass = no. of protons + no. of neutrons

                              13 = 6 + no. of neutrons

                       no. of neutrons = 13 - 6

                                                  = 7

Hence, in a isotope of carbon atom there are 6 protons, 6 electrons and 7 neutrons.

This shows that change in number of neutrons take place according to the definition of an isotope.