Use the periodic table to determine which of the following could be an isotope of bromine (br). check all that apply. z = 79, a = 196 z = 35, a = 79 a = 79, n = 44 z = 44, n = 44

the second and the third represent isotopes of bromine.

Explanation:

1) Isotopes are elements with same atomic number (Z) and different number of neutrons (N)

The atomic number is the number of protons.

2) A is the mass number and it accounts for the sum of the protons (Z) and neutrons (N).

This is A = Z + N.

Remember that is the number of protons, and all the isotopes of bromine have the same atomic number.

4) Let's see at the atomic numbers for each choice:

i) Z = 79, A = 196

This Z is not 35, so it is not an isotope of bromine (it is an isotope of gold)

ii) Z = 35, A = 79

This, indeed, is the isotope of bromine with mass number 79. The information indicates:

Z = atomic number = 35 ⇒ element bromine

A = mass number = 79

N = number of neutrons = A - Z = 79 - 35 = 44 neutrons

iii) A = 79, N = 44

Calculate Z = A - N = 79 - 44 = 35, which indicates it is an isotope of bromine.

iv) Z = 44, N = 44

Z = 44, already states it is not bromine. It is another element, which you can find in the periodic table. It is Rutenium.

Answer : There are two isotopes of Br 79 and Br 81.

So for Br-79 Z = number of protons = 35

N = number of neutrons = 44

A = mass number (Z+N) = 79

Now, for Br-81;

Z = number of protons = 35

N = number of neutrons = 46

A = mass number (Z+N) = 81.