An object that has no element of symmetry is called what?

Options

A. Tetrahedral
B. achiral
C. symmetric
D. asymmetric

Answer

To solve the question "An object that has no element of symmetry is called what?", we need to analyze the options provided and understand the definitions of the terms related to symmetry.

### Step-by-Step Solution:

1. **Understanding Symmetry**:
- Symmetry in chemistry refers to the balanced proportions of a molecule or object. If an object has symmetry, it can be divided into two identical halves.

2. **Analyzing the Options**:
- **Option 1: Tetrahedron**:
- A tetrahedron is a geometric shape with symmetrical properties. It has symmetry because it can be divided into identical halves. Thus, this option cannot be correct.

- **Option 2: A chiral**:
- Chirality refers to the property of a molecule that is not superimposable on its mirror image. A chiral molecule does not have symmetry. However, the term "chiral" itself implies the presence of asymmetry, so this option is also not correct.

- **Option 3: Symmetric**:
- This term directly refers to objects that have symmetry. Therefore, it cannot be the answer to our question, as we are looking for a term that indicates the absence of symmetry.

- **Option 4: Asymmetric**:
- The term "asymmetric" means that an object does not have symmetry. Therefore, it is the correct term for an object that has no element of symmetry.

3. **Conclusion**:
- Based on the analysis of the options, the correct answer to the question is **Option 4: Asymmetric**.

### Final Answer:
An object that has no element of symmetry is called **Asymmetric**.