In this worksheet, we will practice describing common properties of stable isotopes and using shell models to rationalize the existence of magic nuclei.

**Q1: **

Using the Periodic Table, identify which of the following is the most stable isotope.

- A
- B
- C
- D
- E

**Q2: **

Which of the following statements is true?

- AMost stable isotopes contain an even number of protons and an odd number of neutrons.
- BMost stable isotopes contain an odd number of nucleons: isotopes with an even atomic number usually contain an odd number of neutrons, and vice versa.
- CMost stable isotopes contain an odd number of protons and an odd number of neutrons.
- DMost stable isotopes contain an even number of protons and an even number of neutrons.
- EMost stable isotopes contain an even number of nucleons, but there are similar numbers of stable isotopes with odd and even atomic numbers.

**Q3: **

Which of the following is a stable nuclide?

- ANeon-42
- BBarium-83
- CIron-40
- DAluminium-27
- ELithium-12

**Q4: **

Which of the following is a stable nuclide?

- A
- B
- C
- D
- E

**Q5: **

A nuclide contains protons and neutrons. Which of the following expressions is true for most stable nuclides?

- A
- B
- C
- D
- E

**Q6: **

A nuclide is particularly stable if the number of protons or neutrons is equal to one of the magic numbers: 2, 8, 20, 28, 50, 82 and 126. A double magic nuclide is one in which the numbers of protons and neutrons are both magic.

Which of the following nuclides is double magic?

- A
- B
- C
- D
- E

What is the difference between the mass numbers of the two most likely double magic isotopes of tin?

**Q7: **

A nuclide is particularly stable if the number of protons or neutrons is equal to one of the magic numbers: 2, 8, 20, 28, 50, 82 and 126. These nuclides are termed magic.

Which of the following nuclides is not magic?

- A
- B
- C
- D
- E

How many elements in period 4 of the Periodic Table have a magic number of protons?

There is one naturally occurring magic isotope of bismuth. What is the mass number of this isotope?

**Q8: **

Which of the following nuclides has an even number of neutrons?

- A
- B
- C
- D
- E