Which of the following metal is more reactive

Don't be so upset. The reactivity of metals depends on the metallic strength which can be explained by the last question I answered on 16-01-08. First, let me make a simple metallic strength analysis for you and please study it carefully.
When moving down the group, reactivity of a metal ↑: Reason 1: The number of quantum shells [K, L, M,N, O...] ↑(or just shell at cert. level), the distance % nucleus and outermost shell e- ↑, signifying the nuclear attractive force generated by nucleus to the outermost e- becomes ↓. [F = K(Q1Q2)/r2]The weaker the attractive force, the easier the metal to lose an e- (s).Reason 2: Since there is an e- - e- repulsive force % each shells, the actual nuclear attractive force, Z, faced by the outermost shell e- will not equal the nuclear charge. It will be weaker instead. This is called screening /shielding effect(屏蔽效應),σ. Actual nuclear attractive force faced by an outermost shell e- is called effective nuclear charge (有效電荷), Zeff. => Zeff = Z - σ. [有效電荷,即是最外層電子所感受到的原核子吸力 =原核子中質子的吸力減去各層電子層之間的斥力 ]. These two reasons can also be used to explain the metallic bond strength.
When moving across the period,reactivity of a metal↓ Reason 1: the nuclear charge is increasing by +1, implying greater nuclear attractive force, Z, will be generated to the outermost shell e- and as a result, atomic radius ↓. Reason 2: Due to atomic radius ↓, the distance between the nucleus and outermost shell e- ↓. Thus, the nuclear attractive force generated % nucleus and the outermost e- ↑. The outermost e- is difficult to be lost. These two reasons can also be used to explain the metallic bond strength.
For lithium, on the top position of group 1 , with the smallest atomic radius and thus have +3 nuclear charge. [其實正名叫 (very high) charge density(電荷密度).電荷密度 = 原子核的電荷,即是質子的數目除以原子的radius.] . The distance between nucleus the outermost shell e- ↓(只填了K,L shells )[因為原子 半徑細,所以電荷密度會高,引致對外層電子的吸力增大]. The nuclear attractive force % nucleus and outermost shell e- will be greater. Therefore it is difficult for Li to lose its outermost shell e- ,comparing other group 1 metals .當 Li 放進水時,只有嘶嘶聲(hissing sound),並無火出,但是相反Na進水時,個反應激好多,有聲,又有火出.
For barium, nearly on the bottom position of group 2 , with nearly largest atomic radius and thus have +56 nuclear charge . The distance between nucleus the outermost shell e- ↑(填了K,L,M,N, O,P shells )[因為原子 半徑大,所以電荷密度會變低,引致對外層電子的吸力減少]. The The nuclear attractive force % nucleus and outermost shell e- will be weaker. Therefore it is easier for Ba to lose its outermost shell e- .
Which is more reactive? Ans: Ba. Why? Ans: 看上文Depends on what? Ans: 看上文 Is there a pair of elements that has the same reactivity which are from Group 1 and Group 2? 未必有可能. 因為如果是group 2的金屬,它的原子 半徑必定比group1metal為細,因為多了一粒質子之故.所以其對外層電子的吸力也必大之.所以當group 2的金屬失去一粒電子時,它會帶了正電荷,如Ca+.但是你知道,group 2的金屬不會只失去一粒電的,它會失多一粒電子以滿足octet rule,就在這時,不只是原子核會對外層電子有吸力,而最大的吸力則來自金屬帶了的正電荷,所以要失多一粒電子會比之前困難了,因為最外層電子同時被金屬帶了的正電荷及質子所吸引.
% = between ; e- = electron
希望你明白

Lithium is more reactive than Barium.
Lithium is in group 1 of the periodic table.
Barium is in group 2 of the periodic table.
Group 1 elements are more reactive than group 2 element.
So lithium will be more reactive than barium.
It doesn't have a pair of elements that has the same reactivity between Group 1 and Group 2,because they are two group, their properties are not almost the same.So it can't be possible that their reactivity will be same.
Hope that it can help you!!!

Barium is more reactive than Lithium.
In periiodic table, Lithium is in top of group 1.
However, Barium is on the fifth of group 2.
React series in group 1 and 2 are increase down the group.
No pair of elements that has the same reactivity from Group 1 and Group 2.