Photo AI
Define first ionisation energy - Leaving Cert Chemistry - Question 11 - 2013
Question 11
Define first ionisation energy. The graph shows the first ionisation energy values, displayed in order of increasing atomic number, for the first 31 elements of the... show full transcript
Worked Solution & Example Answer:Define first ionisation energy - Leaving Cert Chemistry - Question 11 - 2013
Step 1
Define first ionisation energy.
Answer
First ionisation energy is defined as the minimum energy required to remove the most loosely-bound (highest energy) electron from an isolated (gaseous) atom in its ground (lowest energy) state. This process involves transforming one mole of isolated gaseous atoms into positively charged ions.
Step 2
Step 4
What is the principal reason for the large decrease in first ionisation energy between the elements labelled R and S?
Answer
The large decrease in first ionisation energy between elements R (argon) and S (potassium) is primarily due to the difference in electronic configurations. Potassium has a higher energy level and a more stable electron shell configuration compared to argon, leading to a reduced attraction between the nucleus and the outermost electron.
Step 5
Explain why the first ionisation energy value of the element labelled H is lower than that of the element labelled G.
Answer
The first ionisation energy value of element H (oxygen) is lower than that of element G (nitrogen) because oxygen has a half-full p subshell that is less stable than the half-full configuration of nitrogen. Oxygen's configuration has paired electrons in the 2p subshell, leading to electron repulsion, which makes it easier to remove an electron compared to nitrogen which has its electrons singly occupied, maintaining greater stability.