Answer:
31
Explanation:
Given parameters:
Mass number = 66
Number of electrons = 35
Unknown:
Number of electrons
Solution:
In an atom, the number of protons and electrons are the same. In ions, there is a difference between the two numbers.
For this problem, once we can find the number of protons, it is therefore the number of electrons.
Mass number = number of protons + number of neutrons
Insert the parameters and solve;
66 = number of protons + 35
Number of protons = 66 - 35 = 31
So the number of electrons is 31
