1) Rank these elements according to electron affinity: Ga Br Kr

2. Arrange these elements according to atomic radius (largest to smallest): Sr Ba Be Ca Mg

3. Arrange these elements according to atomic radius (largest to smallest): Be B C N O F Ne Li

4. Rank these elements according to first ionization energy (highest to lowest): Na Li Rb K

5. Rank these elements according to first ionization energy (highest to lowest): K Ca Ga Ge As Se Br Kr

Answer:

electron affinity increases across the period from left to right in the peiodic
table .except zero group.they have 0 electron affinity. Since given elements belongs to
3rd period, their electron affinity from least to most as follows

Kr < Ga < Br

Atomic radius increases down the group.Given elements belongs to 2nd group
in the periodic table.
they can be arranged in the decreasng order of atomic radius as given

Ba > Sr > Ca > Mg > Be

from left to right across a period atomic radius decreases. These elements
are members of 2 nd period can be arranged from largest to smallest as given

Li > Be > B > C >N >O >F Ne

ionization energy decreases as we go down the group.it is due to the increase in atomic radius
from highest to lowest given below

Li > Na > K > Rb

5)Ioniztion energy increases across the period from left to right
from highest to lowest given below

Kr > Br > Se > As > Ge > Ga > Ca > K