Periodic Classification and Periodic Properties - Result Question 18
####15. The incorrect statement among the following. (1997(C), 1M)
(a) The first ionisation potential of $Al$ is less than the first ionisation potential of $Mg$
(b) The second ionisation potential of $Mg$ is greater than the second ionisation potential of $Na$
(c) The first ionisation potential of $Na$ is less than the first ionisation potential of $Mg$
(d) The third ionisation potential of $Mg$ is greater than third ionisation potential of $Na$
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Answer:
Correct Answer: 15. (b)
Solution:
- (a) Correct statement In a period, element of 2nd group has higher first ionisation potential than element of group 13.
(b) Incorrect statement $Mg^{+}$require less energy for further ionisation than $Na^{+}$because of noble gas configuration of $Na^{+}$.
(c) Correct statement Ionisation energy increases from left to right in a period.
