Column A

Question

1.
How many protons does the Br-1 ion have? (The atomic number tells you the number of protons)

2.
How many neutrons does the Br-1 ion have? (Remember: mass number - atomic number = # neutrons)

3.
How many electrons does the Br-1 ion have? (Remember: if the ion is negative, it has gained electrons. To find the number of electrons, take the atomic number and add the charge of the ion.)

Column B
a.45
b.115
c.34
d.36
e.35
f.16

Answer 1

Column A
1. The Br-1 ion has 35 protons. (The atomic number of Br is 35)

2. The Br-1 ion has 45 neutrons. (The mass number of Br is 80 and the atomic number is 35, so subtracting 35 from 80 gives 45)

3. The Br-1 ion has 36 electrons. (The atomic number of Br is 35 and the charge of the ion is -1, so adding 35 and -1 gives 36)

Column B
a. 45 (Matches with the number of neutrons in Br-1)
b. 115 (No match)
c. 34 (No match)
d. 36 (Matches with the number of electrons in Br-1)
e. 35 (No match)
f. 16 (No match)