Answer Key — Isotopes Worksheet
A. Fill in the Blanks
- Protons
- Protons
- Neutrons
- Mass
- Atomic
B. True or False
- True
- False
- True
- True
- False
C. Complete the Table
| Isotope | Protons | Neutrons | Mass Number |
|---|---|---|---|
| Carbon-12 | 6 | 6 | 12 |
| Carbon-14 | 6 | 8 | 14 |
| Oxygen-16 | 8 | 8 | 16 |
| Oxygen-18 | 8 | 10 | 18 |
| Chlorine-35 | 17 | 18 | 35 |
D. Identify the Isotope
- Carbon-12
- Carbon-14
- Oxygen-18
- Chlorine-35
E. Think and Answer
- Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
- They have the same atomic number because they have the same number of protons.
- Carbon-12 has 6 neutrons, while Carbon-14 has 8 neutrons. Both have 6 protons.
- 12 neutrons
Calculation: 23 − 11 = 12
- 25
Calculation: 12 + 13 = 25
- They have the same number of protons (and therefore the same atomic number), but different numbers of neutrons.