The element with smallest value of ionization energy is
Correct answer: D. Ba
- A. Li
- B. Al
- C. Ca
- D. Ba
Explanation
Ionisation energy falls down a group as the outer electron lies further from the nucleus and is better shielded, and barium is the lowest of these four in the periodic table. Lithium is small and holds its outer electron tightly by comparison. Across a period the trend runs the other way, which is why aluminium is not the answer despite being a metal.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Periodic Properties and Trends
Periodic properties arise from electron configuration and effective nuclear charge, producing trends in atomic and ionic radius, ionization energy, electron affinity, electronegativity, metallic character and reactivity. Comparisons run across periods and down groups, with attention to common exceptions. The topic also relates these trends to the behavior of s-block and p-block elements.
Practise s-Block and p-Block Elements
1,359 free s-Block and p-Block Elements MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Periodic Properties and Trends questions
Lithium shows a diagonal relationship with
The oxides of the elements across period 3, from sodium to sulphur, change from
Across a period, the first ionisation energy generally
Identify among the following elements that does NOT belong to VIIA group
What is the chemical symbol of "Potassium"?
In Periods from Left to right Electronegativity will: _________?