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Which atom has the greatest first ionisation energy? A H B He C Li D Ne - AQA - A-Level Chemistry - Question 14 - 2019 - Paper 3
Question 14
Which atom has the greatest first ionisation energy? A H B He C Li D Ne
Worked Solution & Example Answer:Which atom has the greatest first ionisation energy? A H B He C Li D Ne - AQA - A-Level Chemistry - Question 14 - 2019 - Paper 3
Step 1
Step 2
Determine the first ionisation energy trends
Answer
First ionisation energy generally increases across a period in the periodic table due to increasing nuclear charge, which attracts the electrons more strongly. Additionally, it generally decreases down a group due to increased distance between the nucleus and the outermost electrons.
Step 3
Analyze each option
Answer
- H (Hydrogen) has a lower first ionisation energy compared to Helium.
- He (Helium) has a higher first ionisation energy due to its lack of shielding and greater effective nuclear charge.
- Li (Lithium) has a lower first ionisation energy as it is in the same group as H but further down, which increases distance from the nucleus.
- Ne (Neon) has a high first ionisation energy as it is a noble gas with a full outer shell.
Step 4