Elements in the same group (vertical columns) have the same number of valence electrons. These elements behave similarly because they will either give up or take the same number of electrons to fill their valence shell. Since potassium has 1 valence electron, it will most likely give up one electron. Out of all of the answer options, the only element that is in the same group as potassium is francium.
It'll be the same as 58.44 amu. This is because of the law of conservation of mass which states that total mass of reactants is always equal to the total mass of products formed.
