Total Numbers of elements which are belong to same period(III).
Li,Na,Mg,F,Ne,Sc,P,Ar

Explanation

To solve the question regarding the total number of elements that belong to the same period (III), we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements Provided**: The elements given in the question are:
- Li (Lithium)
- Na (Sodium)
- Mg (Magnesium)
- F (Fluorine)
- Ne (Neon)
- Sc (Scandium)
- P (Phosphorus)
- Ar (Argon)

2. **Recall the Periodic Table Structure**:
- The periodic table is organized into periods (horizontal rows) and groups (vertical columns).
- Period 1 contains H and He.
- Period 2 contains Li, Be, B, C, N, O, F, Ne.
- Period 3 contains Na, Mg, Al, Si, P, S, Cl, Ar.
- Scandium (Sc) is a d-block element and starts from the fourth period.

3. **Determine the Elements in Period 3**:
- From the periodic table, the elements in Period 3 are:
- Na (Sodium)
- Mg (Magnesium)
- Al (Aluminum)
- Si (Silicon)
- P (Phosphorus)
- S (Sulfur)
- Cl (Chlorine)
- Ar (Argon)

4. **Check Each Element from the List**:
- **Li**: Belongs to Period 2 (not included)
- **Na**: Belongs to Period 3 (included)
- **Mg**: Belongs to Period 3 (included)
- **F**: Belongs to Period 2 (not included)
- **Ne**: Belongs to Period 2 (not included)
- **Sc**: Belongs to Period 4 (not included)
- **P**: Belongs to Period 3 (included)
- **Ar**: Belongs to Period 3 (included)

5. **Count the Elements in Period 3**:
- The elements from the original list that belong to Period 3 are:
- Na, Mg, P, Ar
- Therefore, there are a total of **4 elements** that belong to Period 3.

### Final Answer:
The total number of elements that belong to the same period (III) is **4**.

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