Ionization Enthalpy Numerical
If first ionization enthalpy values are Na = 496 kJ mol^-1, Mg = 738 kJ mol^-1 and Al = 578 kJ mol^-1, which statement is correct?
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About This Question
- Subject
- chemistry
- Chapter
- classification of elements and periodicity in properties
- Topic
- ionization enthalpy numerical
- Difficulty
- Hard
- Year
- 2025
Solution
Correct Answer:
Al has lower first ionization enthalpy than Mg due to electron removal from 3p orbital
The general trend in a period is increasing ionization enthalpy, but Mg to Al is a known exception. Mg has a filled 3s2 subshell, whereas Al has 3s2 3p1 and the 3p electron is higher in energy and easier to remove. Hence Al shows lower first ionization enthalpy than Mg, consistent with the given values in kJ mol^-1.
This hard difficulty chemistry question is from the chapter classification of elements and periodicity in properties, covering the topic of ionization enthalpy numerical. It appeared in the 2025 exam.
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