Actinide that is naturally available with highest isotopic number

Options

A. U
B. Pu
C. Cu
D. Fm

Answer

To solve the question about the actinide that is naturally available with the highest isotopic number, we can follow these steps:

### Step 1: Understand the Concept of Isotopes
Isotopes are variants of a particular chemical element that have the same number of protons (same atomic number) but different numbers of neutrons, resulting in different mass numbers.

**Hint:** Remember that isotopes are defined by their mass number, which is the sum of protons and neutrons in the nucleus.

### Step 2: Identify the Actinides
The actinide series includes elements with atomic numbers from 89 (actinium) to 103 (lawrencium). The actinides are known for having multiple isotopes.

**Hint:** Familiarize yourself with the actinide series and their atomic numbers.

### Step 3: Research the Isotopes of Actinides
Among the actinides, uranium (U) is well-known for having several isotopes. The most common isotopes of uranium are:
- Uranium-238 (U-238)
- Uranium-235 (U-235)
- Uranium-234 (U-234)

**Hint:** Look for the isotopes of each actinide to determine which has the highest mass number.

### Step 4: Determine the Highest Isotopic Number
Among the naturally occurring actinides, uranium-238 has the highest mass number (238). Other actinides such as thorium (Th) and plutonium (Pu) have isotopes, but none exceed the mass number of uranium-238.

**Hint:** Compare the mass numbers of the isotopes of each actinide to find the maximum.

### Step 5: Conclusion
The actinide that is naturally available with the highest isotopic number is uranium (specifically, uranium-238).

**Final Answer:** Uranium (U-238) is the actinide with the highest isotopic number that is naturally available.