To determine which isotope or ion contains 35 protons, 46 neutrons, and 36 electrons, let’s break down the information provided:
- The number of protons in an atom defines the element. Here, we have 35 protons, which corresponds to the element bromine (Br).
- The number of neutrons gives us the isotope of that element. With 46 neutrons, we can calculate the mass number: mass number = protons + neutrons = 35 + 46 = 81.
- The number of electrons tells us about the charge of the ion. In this case, there are 36 electrons. Since there are more electrons than protons, the ion has a negative charge (anion).
Now let’s review the options:
- a) 81Kr+ – This is krypton, which cannot be correct as it has 36 protons.
- b) 81Br – This is the neutral bromine isotope (35 protons, 46 neutrons, and 35 electrons).
- c) 81Kr – Again, this is krypton and not the right answer.
- d) 81Br– – This represents bromine with 35 protons, 46 neutrons, and 36 electrons, making it a bromide ion.
Based on this analysis, the correct answer is d) 81Br–.