Question

6. Based on their positions in the periodic table, which element would you expect to have the lowest first ionization energy

fluorine (F)
iodine (I)
lithium (Li)
rubidium (Rb)

Answer 1

Ionization energy decreases as u move from top to bottoms and and increases as u go from left to right

Answer 2

oh ok thank you can I ask another one?

Answer 3

lowest first ionization enthalpy is of metals only & there are only 2 metals in the given question that are rubidium and lithium.
since rubidium has bigger size down the group than lithium, thus effective nuclear charge decrease as the no. of shells increase down the group.
therefore rubidium has lowest first ionization enthalpy.