The basis for the classification of elements in the modern periodic table is

Options

A. Atomic Number
B. Atomic weight
C. Atomic volume
D. Equivalent weight

Answer

To solve the question regarding the basis for the classification of elements in the modern periodic table, we can follow these steps:

### Step 1: Understand the Options
The question provides four options:
1. Atomic number
2. Atomic weight
3. Atomic volume
4. Equivalent weight

### Step 2: Review the Modern Periodic Law
The modern periodic table is organized based on the periodic law, which states that the physical and chemical properties of elements are periodic functions of their atomic numbers.

### Step 3: Identify the Correct Basis
- **Atomic Number**: This is the number of protons in the nucleus of an atom and is the primary basis for the arrangement of elements in the modern periodic table.
- **Atomic Weight**: While this was used in earlier periodic tables, it is not the basis for the modern classification.
- **Atomic Volume**: This is not a basis for classification in the periodic table.
- **Equivalent Weight**: This is related to the reactivity of elements but does not serve as a basis for classification.

### Step 4: Conclusion
Based on the periodic law, the correct answer is that the modern periodic table is classified based on the atomic number of the elements.

### Final Answer
The basis for the classification of elements in the modern periodic table is **atomic number**.

---