Q628
The element with highest first ionisation energy is
A.
Hydrogen
B.
Helium
AnswerC.
Lithium
D.
Sodium
Answer: Option B
Solution
Answer: Option B
Solution:
The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.