Transition elements have greater tendency to form complexes because

Options

A. They have vacant d-orbitals
B. They have large size
C. They show variable oxidation state
D. They have two electrons in their outermost shells.

Answer

To answer the question "Transition elements have greater tendency to form complexes because," we will analyze the reasons behind this tendency step by step.

### Step 1: Understanding Transition Elements
Transition elements, also known as d-block elements, are characterized by their electronic configuration, which typically includes partially filled d-orbitals. Their general electronic configuration can be represented as \( (n-1)d^{1-10} ns^{0-2} \).

**Hint:** Remember that the presence of d-orbitals is crucial for complex formation.

### Step 2: Vacant d-Orbitals
One of the primary reasons transition metals can form complexes is that they have vacant d-orbitals. When ligands approach these metals, they can donate electron pairs to these vacant d-orbitals, leading to the formation of coordinate covalent bonds.

**Hint:** Think about how ligands interact with the metal ions through their electron pairs.

### Step 3: Variable Oxidation States
Transition metals exhibit variable oxidation states due to the involvement of both their d and s electrons in bonding. This variability allows them to form different types of complexes depending on the oxidation state of the metal ion.

**Hint:** Consider how different oxidation states can lead to different coordination numbers and geometries in complexes.

### Step 4: Size of Transition Metals
While the size of transition metals is often smaller compared to s-block elements, this is not a direct reason for their ability to form complexes. The smaller size allows for a higher charge density, which can enhance the interaction with ligands.

**Hint:** Focus on the relationship between size, charge, and the ability to attract ligands.

### Step 5: Electrons in the Outermost Shell
Transition metals typically have two electrons in their outermost shell (s-orbital), which can be lost easily. This loss of electrons contributes to the formation of positive ions, which can then coordinate with ligands.

**Hint:** Think about how losing electrons can facilitate the formation of complexes.

### Conclusion
In summary, transition elements have a greater tendency to form complexes primarily due to:
1. The presence of vacant d-orbitals that can accept electron pairs from ligands.
2. Their ability to exhibit variable oxidation states, allowing for diverse complex formation.
3. The presence of two electrons in their outermost shell that can be easily lost.

### Final Answer
Transition elements have a greater tendency to form complexes because they have vacant d-orbitals, exhibit variable oxidation states, and have two electrons in their outermost shell that can be easily lost.