Classification Of Elements And Periodicity In Properties Ques 224
Question: Ionisation energy in group I-A varies in the decreasing order as [Orissa JEE 2005]
Options:
A) $ Li>Na>K>Cs $
B) $ Na>Li>K>Cs $
C) $ Li>Cs>K>Na $
D) $ K>Cs>Na>Li $
Show Answer
Answer:
Correct Answer: A
Solution:
Due to the large size of group IA elements, the outermost electron is far from the nucleus and can easily be removed. their ionisation energies or ionisation potentials are relatively low. Li Na K Rb Cs Ionisation potential (eV) 5.4 5.1 4.3 4.2 3.9
