Which has maximum radioactive activity :

Options

A. Uranium
B. Plutonium
C. Radium
D. Thorium

Explanation

To determine which radioactive element has maximum radioactive activity, we need to analyze the properties of the given elements. Here is a step-by-step solution:

### Step 1: Understand Radioactive Activity
Radioactive activity is defined as the rate at which a sample of radioactive material decays. It is often measured in terms of half-life, which is the time required for half of the radioactive atoms in a sample to decay.

**Hint:** Remember that shorter half-lives indicate higher radioactive activity.

### Step 2: Identify the Elements
In this case, we are comparing different radioactive elements. One of the elements mentioned is radium (Ra).

**Hint:** Make sure to list all the radioactive elements provided in the question for comparison.

### Step 3: Analyze Radium
Radium-226 is a common isotope of radium. It is known for its significant radioactive properties. Radium is part of the decay chain of uranium and decays into radon gas, which is a noble gas.

**Hint:** Look at the decay products of each element to understand their stability and activity.

### Step 4: Compare with Other Elements
When comparing radium with other radioactive elements (like uranium, thorium, etc.), we need to consider their half-lives. Radium-226 has a half-life of about 1600 years, which is relatively short compared to some other isotopes.

**Hint:** Check the half-lives of the other radioactive elements to see how they compare to radium.

### Step 5: Conclusion
Given that radium has a shorter half-life and its decay product is radon gas (a stable noble gas), radium exhibits maximum radioactive activity among the elements being compared.

**Final Answer:** Radium has maximum radioactive activity.