Answer:
Step-by-step explanation:
Here, we want to make a comparism between isotopes
Firstly,we need to know what these are
Isotopes are the different kinds of the same atom or element. The principal difference in terms of atomic composition is that isotopes have the same number of protons (they have same atomic number) but differenet number of neutrons which means they have didderenet mass numbers
Now, let us look at the values given
Bromine has an atomic number of 35, which is the number of protons in the nucleus of its atom
We can see we have two differenet mass number (it is the sum of the number of protons and the number of neutrons in the nucleus of an atom) given. These mass numbers differ in the number of neutrons
The number of neutrons in Br-79 will be 79 - 35 = 44
For Br-81, the number of neutrons will be 81-35 = 46
Now,let us write the composition as stated
Br- 79 : 35 protons and 44 neutrons (35 electrons too since it is a neutral atom)
Br-81 : 35 protons and 46 neutrons (35 electrons)
Kindly understand that the number of electrons and protons are the same for a neutral atom