Question
Question: The set representing the correct order of first ionisation potential is :...
The set representing the correct order of first ionisation potential is :
A
K < Na < Li
B
Be > Mg > Ca
C
B > C > N
D
Ge > Si > C
Answer
K < Na < Li
Explanation
Solution
Down the group size increases and, therefore, attraction between valence shell electron and nucleus decreases and thus ionisation energy decrease.
Along the period the atomic size decreases and nuclear charge increases. So generally the ionization energy increases. However, half-filled and completely filled valence shell electron also affect the ionization energy along the period