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Define first ionisation energy - Leaving Cert Chemistry - Question b - 2014
Question b
Define first ionisation energy. Explain why the first ionisation energy value of silicon is (i) greater than that of aluminium, (ii) less than that of carbon.
Worked Solution & Example Answer:Define first ionisation energy - Leaving Cert Chemistry - Question b - 2014
Step 1
Step 2
Explain why the first ionisation energy value of silicon is greater than that of aluminium.
Answer
The first ionisation energy of silicon is greater than that of aluminium because of the greater nuclear charge in silicon. As the number of protons in the nucleus increases, it exerts a stronger force on the electrons, making them harder to remove. This results in a higher ionisation energy.
Step 3
Explain why the first ionisation energy value of silicon is less than that of carbon.
Answer
The first ionisation energy of silicon is less than that of carbon due to its larger atomic radius. As silicon has more electron shells than carbon, its outermost electron is farther away from the nucleus. This distance results in reduced electrostatic attraction, thus requiring less energy to remove the outermost electron.