Elements which generally exhibit multiple oxidation states and whose ions are usually coloured are

Options

A. Metalloids
B. Transition elements
C. Non - metals
D. Gasses

Answer

To solve the question, "Elements which generally exhibit multiple oxidation states and whose ions are usually coloured are," we can follow these steps:

### Step 1: Identify the Type of Elements
The question is asking about elements that exhibit multiple oxidation states and have colored ions. The elements that fit this description are typically the transition metals.

**Hint:** Think about the periodic table and which groups of elements are known for having variable oxidation states.

### Step 2: Understand the Reason for Multiple Oxidation States
Transition metals can exhibit multiple oxidation states due to the presence of vacant d-orbitals. These d-orbitals can participate in bonding and allow for the loss of different numbers of electrons, leading to various oxidation states.

**Hint:** Recall the electron configuration of transition metals and how it relates to their ability to lose electrons.

### Step 3: Explain the Color of Ions
The colored nature of the ions of transition metals is primarily due to d-d transitions. When light hits these ions, electrons in the d-orbitals can be excited from a lower energy level to a higher energy level, resulting in the absorption of specific wavelengths of light and the appearance of color.

**Hint:** Consider how electron transitions in d-orbitals can affect the absorption of light.

### Step 4: Write the General Electronic Configuration
The general electronic configuration of transition metals can be represented as:
\[ \text{Noble gas} \, (n-1)d^{1-10} \, ns^{0-2} \]
This configuration indicates that the d-orbitals are being filled and can be involved in oxidation state changes.

**Hint:** Familiarize yourself with the periodic table and the electronic configurations of transition metals.

### Step 5: Conclude the Answer
Based on the above points, we conclude that the elements which generally exhibit multiple oxidation states and whose ions are usually colored are the **transition metals**.

**Final Answer:** Transition metals.