For which elements, Newlands' law of octaves is not applicable?

Options

A. Ne
B. Ti
C. Kr
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Newlands' Law of Octaves**: Newlands' Law of Octaves states that when elements are arranged in order of increasing atomic mass, every eighth element exhibits similar properties. This was an early attempt to classify elements based on their properties.

2. **Limitations of Newlands' Law**: The law was found to be applicable only to the first 20 elements of the periodic table. Beyond these 20 elements, the pattern of similar properties every eighth element does not hold true.

3. **Identifying the First 20 Elements**: The first 20 elements, in order of increasing atomic mass, are:
- Hydrogen (H)
- Helium (He)
- Lithium (Li)
- Beryllium (Be)
- Boron (B)
- Carbon (C)
- Nitrogen (N)
- Oxygen (O)
- Fluorine (F)
- Neon (Ne)
- Sodium (Na)
- Magnesium (Mg)
- Aluminium (Al)
- Silicon (Si)
- Phosphorus (P)
- Sulfur (S)
- Chlorine (Cl)
- Argon (Ar)
- Calcium (Ca)
- Scandium (Sc)

4. **Identifying Elements Outside the First 20**: Elements that are not part of the first 20 elements include:
- Titanium (Ti) with atomic number 22
- Krypton (Kr) with atomic number 36

5. **Conclusion**: Therefore, elements such as Titanium and Krypton do not follow Newlands' Law of Octaves since they are outside the range of the first 20 elements.

**Final Answer**: Newlands' Law of Octaves is not applicable to elements such as Titanium (Ti) and Krypton (Kr).

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