Question detail
How does the first ionisation energy of phosphorus compare to that of silicon?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Periodicity
Question
- A. Phosphorus has a higher first ionisation energy than silicon.
- B. Phosphorus has a lower first ionisation energy than silicon.
- C. They have the same first ionisation energy.
- D. Silicon has a higher first ionisation energy than phosphorus.
Answer
Phosphorus has a higher first ionisation energy than silicon.
Explanation
Phosphorus has a higher first ionisation energy than silicon due to its higher effective nuclear charge, which increases the attraction between the nucleus and the outer electrons.
Common mistake
Misunderstanding Ionisation Energy Trends
Students often confuse the trend in first ionisation energy across Period 3 with atomic radius, thinking that ionisation energy decreases as atomic radius increases.
To clarify, remember that first ionisation energy increases across Period 3 due to increased nuclear charge attracting electrons more strongly. Use the formula for ionisation energy trends: as atomic number increases, ionisation energy increases because of greater effective nuclear charge. Therefore, the correct trend is that first ionisation energy increases across Period 3.
Related flashcards
Flashcard 1 of 5
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.