The hardest metal from the following is :

Options

A. Gold
B. Iron
C. Platinum
D. Tungsten

Explanation

To determine the hardest metal from the given options, we can follow these steps:

### Step 1: Understand the properties of metals
Metals are known for their hardness, malleability, ductility, and good conductivity. Hardness is an important property that can vary significantly among different metals.

### Step 2: Review the metals listed
We need to identify the metals mentioned in the video transcript: iron, gold, platinum, and tungsten.

### Step 3: Compare the atomic sizes
According to the transcript, the order of atomic size from smallest to largest is:
1. Iron
2. Gold
3. Platinum
4. Tungsten

### Step 4: Analyze the relationship between atomic size and hardness
The transcript states that hardness increases with an increase in atomic size. Therefore, the metal with the largest atomic size will be the hardest.

### Step 5: Identify the hardest metal
From the list, tungsten has the largest atomic size, which means it is the hardest metal among the options provided.

### Conclusion
Thus, the hardest metal from the options given is **Tungsten**.

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