Ligand with two or more points of attachment to single metal atoms are called .

Options

A. Monodentate ligand
B. Chelating ligand
C. Ambidentate ligand
D. None of these

Answer

To solve the question, "Ligands with two or more points of attachment to a single metal atom are called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ligands**:
- Ligands are ions or molecules that can donate a pair of electrons to a metal atom to form a coordinate bond.

2. **Identifying Types of Ligands**:
- Ligands can be classified based on the number of donor atoms they have:
- **Monodentate Ligands**: These ligands have only one donor atom. For example, water (H₂O) and ammonia (NH₃) are monodentate ligands.
- **Bidentate Ligands**: These ligands have two donor atoms. An example is ethylene diamine (NH₂CH₂CH₂NH₂), which has two nitrogen atoms that can donate lone pairs.
- **Polydentate Ligands**: These ligands have multiple donor atoms. A well-known example is EDTA (ethylenediaminetetraacetic acid), which can bind to a metal ion at multiple sites.

3. **Focusing on the Question**:
- The question specifically asks for ligands with "two or more points of attachment." This indicates that we are looking for ligands that can attach to a metal atom at multiple sites.

4. **Identifying the Correct Type**:
- From the definitions:
- Monodentate ligands do not fit the requirement as they have only one attachment point.
- Bidentate ligands fit the requirement as they have two attachment points.
- Polydentate ligands also fit since they can have three or more attachment points.

5. **Conclusion**:
- The term that best describes ligands with two or more points of attachment is **Chelating Ligands**. Chelating ligands can attach to a metal atom at multiple sites, forming stable complexes.

### Final Answer:
- **Chelating Ligands** are the ligands with two or more points of attachment to a single metal atom.

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