Periodic Classification and Periodic Properties - Result Question 22
####19. The first ionisation potential of $Na, Mg, Al$ and $Si$ are in the order
(a) $Na
(b) $Na>Mg>Al>Si$
(c) $Na<Mg
(d) $Na>Mg>Al<Si$
(1988, 1M)
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Answer:
Correct Answer: 19. (c)
Solution:
- Ionisation energy increases from left to right in a period. However, exception occur between group 2 and group 13 elements on account of stability of electronic configuration of valence shell.
$\Rightarrow$ The desired order is $Na
