What is the total number of inner transition elements in the periodic table?

Options

A. 10
B. 14
C. 30
D. 28

Explanation

To determine the total number of inner transition elements in the periodic table, we will follow these steps:

### Step 1: Understand Inner Transition Elements
Inner transition elements primarily refer to the f-block elements in the periodic table. These elements are characterized by the filling of f-orbitals.

**Hint:** Remember that the f-block elements are divided into two series: lanthanides and actinides.

### Step 2: Identify the Lanthanides
The lanthanides consist of the 4f series. There are a total of 14 elements in this series, ranging from lanthanum (La) to lutetium (Lu).

**Hint:** Count the elements from atomic number 57 (La) to atomic number 71 (Lu) to confirm the total.

### Step 3: Identify the Actinides
The actinides consist of the 5f series. Similar to the lanthanides, there are also 14 elements in this series, ranging from actinium (Ac) to lawrencium (Lr).

**Hint:** Count the elements from atomic number 89 (Ac) to atomic number 103 (Lr) to verify the total.

### Step 4: Calculate the Total Number of Inner Transition Elements
Now, add the number of lanthanides and actinides together:
- Number of lanthanides = 14
- Number of actinides = 14

Total inner transition elements = 14 (lanthanides) + 14 (actinides) = 28.

**Hint:** Ensure you are adding the two series correctly to find the total.

### Conclusion
The total number of inner transition elements in the periodic table is **28**.

**Final Answer:** 28 (Option 4 is correct).

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