Which of the following shows an oxidation state of +8?

Options

A. Rh
B. Os
C. Pd
D. Pt

Explanation

To determine which of the given elements shows an oxidation state of +8, we will analyze each option: rhodium, osmium, palladium, and platinum.

### Step 1: Identify the elements and their atomic numbers.
- **Rhodium (Rh)**: Atomic number 45
- **Osmium (Os)**: Atomic number 76
- **Palladium (Pd)**: Atomic number 46
- **Platinum (Pt)**: Atomic number 78

**Hint:** Look up the atomic numbers of the elements to understand their position in the periodic table.

### Step 2: Write the electronic configurations of the elements.
- **Rhodium (Rh)**: [Kr] 4d^7 5s^2
- **Osmium (Os)**: [Xe] 4f^14 5d^6 6s^2
- **Palladium (Pd)**: [Kr] 4d^10
- **Platinum (Pt)**: [Xe] 4f^14 5d^9 6s^1

**Hint:** The electronic configuration helps in understanding how many valence electrons are available for bonding.

### Step 3: Determine the maximum oxidation states of each element.
- **Rhodium (Rh)**: Maximum oxidation state is +6.
- **Osmium (Os)**: Maximum oxidation state is +8.
- **Palladium (Pd)**: Maximum oxidation state is +4.
- **Platinum (Pt)**: Maximum oxidation state is +4.

**Hint:** The maximum oxidation state can often be found by considering the number of valence electrons and how they can participate in bonding.

### Step 4: Analyze why osmium can exhibit a +8 oxidation state.
Osmium has a unique electronic configuration that allows it to utilize both its 5d and 6s electrons for bonding. This results in a higher oxidation state. Specifically, it can lose all six 5d electrons and two 6s electrons, leading to an oxidation state of +8.

**Hint:** Consider how the energy levels of the orbitals allow electrons to be removed for bonding.

### Step 5: Conclusion
Among the given options, **osmium (Os)** is the only element that shows an oxidation state of +8.

**Final Answer:** The element that shows an oxidation state of +8 is **Osmium (Os)**.