Rydberg constant is

Options

A. Same for all elements
B. Different for different elements
C. A universal constant
D. Is different for lighter elements but same for heavier elements

Explanation

**Step-by-Step Solution:**

1. **Definition of Rydberg Constant**: The Rydberg constant (R_H) is a physical constant related to atomic spectra. It is used to predict the wavelengths of spectral lines in many chemical elements.

2. **Formula**: The Rydberg constant can be expressed mathematically as:
\[ R_H = R_\alpha \cdot Z^2 \]
where \( R_\alpha \) is a constant value and \( Z \) is the atomic number of the element.

3. **Dependence on Atomic Number**: The Rydberg constant is dependent on the atomic number \( Z \). This means that different elements will have different Rydberg constants because they have different atomic numbers.

4. **Comparison Between Elements**: For heavier elements, the Rydberg constant tends to be similar, while for lighter elements, the values can differ more significantly. This is due to the effects of electron shielding and other quantum mechanical factors.

5. **Conclusion**: Therefore, the Rydberg constant is not the same for all elements; it varies depending on the atomic number of the element.

**Final Answer**: The Rydberg constant is different for different elements, depending on their atomic number \( Z \).

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