# Lesson Worksheet: Properties of Stable Nuclei Chemistry

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

**Q1: **

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

**Q2: **

Which of the following is a stable nuclide?

- ABarium-83
- BNeon-42
- CIron-40
- DAluminum-27
- ELithium-12

**Q3: **

Which of the following is the most stable nuclide of an element?

- A
- B
- C
- D
- E

**Q4: **

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

- A
- B
- C
- D
- E

**Q5: **

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?

**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. 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?

**Q7: **

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

- A
- B
- C
- D
- E