Modern periodic table is based on

Options

A. atomic mass
B. mass number
C. atomic number
D. electronic configuration

Explanation

**Step-by-Step Solution:**

1. **Understanding the Modern Periodic Table**: The modern periodic table is a systematic arrangement of elements based on certain principles that dictate how elements are organized.

2. **Historical Context**: The modern periodic table was developed by Dmitri Mendeleev, who initially arranged elements according to their atomic masses. However, this arrangement had limitations.

3. **Key Principle**: The modern periodic table is primarily based on the atomic number of elements. The atomic number is the number of protons in the nucleus of an atom and determines the identity of the element.

4. **Trends in the Periodic Table**: When elements are arranged by atomic number, various trends can be observed:
- **Groups**: Elements in the same group (vertical columns) exhibit similar chemical and physical properties.
- **Periods**: As you move across a period (horizontal rows), the properties of elements change in a predictable manner.

5. **Why Atomic Number?**: The atomic number provides a more accurate representation of an element's properties compared to atomic mass. Elements with the same atomic number have the same number of protons and, therefore, similar chemical behavior.

6. **Conclusion**: The modern periodic table is based on the atomic number of elements, which allows for a more coherent organization that reflects the similarities and trends in elemental properties.

**Final Answer**: The modern periodic table is based on the atomic number of elements.

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