(Sodium) #Na# atom is more likely to give electron in Gaseous state because its first Ionization energy is less than (Lithium) #Li# .
Explanation:
This is because the size of #Na##(g)# atom is bigger than the (Lithium) #Li ##(g)# atom due to the presence of one more Shell.
Thus the outermost #e^-#of #Na##(g)#atom is far away from nucleus than the outermost #e^-#in #Li##(g)# atom, so it is more easy for the #e^-# to be released from #Na##(g)#atom.