`""_(92)^(235)U, ""_(92)^(238)U` and `""_(92)^(239)U` are

Options

A. isomers
B. isotopes
C. isobars
D. Isotones

Explanation

To solve the question regarding the nature of the elements \( _{92}^{235}U, _{92}^{238}U, \) and \( _{92}^{239}U \), we need to analyze the definitions of isomers, isotopes, isobars, and isotones.

### Step-by-Step Solution:

1. **Identify the Atomic Number:**
- All three elements \( _{92}^{235}U, _{92}^{238}U, \) and \( _{92}^{239}U \) have the same atomic number, which is 92. This indicates that they are all isotopes of uranium.

**Hint:** The atomic number indicates the number of protons in the nucleus and defines the element.

2. **Identify the Mass Numbers:**
- The mass numbers for the three isotopes are:
- \( _{92}^{235}U \) has a mass number of 235.
- \( _{92}^{238}U \) has a mass number of 238.
- \( _{92}^{239}U \) has a mass number of 239.
- Since the mass numbers are different, this confirms that they are isotopes.

**Hint:** The mass number is the sum of protons and neutrons in the nucleus.

3. **Define Isotopes:**
- Isotopes are defined as atoms of the same element (same atomic number) that have different mass numbers (different numbers of neutrons).

**Hint:** Look for elements with the same atomic number but different mass numbers to identify isotopes.

4. **Conclusion:**
- Since \( _{92}^{235}U, _{92}^{238}U, \) and \( _{92}^{239}U \) all have the same atomic number (92) but different mass numbers (235, 238, and 239), they are classified as isotopes.

**Final Answer:** The elements \( _{92}^{235}U, _{92}^{238}U, \) and \( _{92}^{239}U \) are **isotopes**.