Why might two elements possess similar chemical properties?

because they are close to each on the or in the same group as each other on the table of elements. also they have the same number of electrons

Explanation:

Elements which have same number of valence electrons generally show similar chemical properties.

Therefore, elements of same group have similar chemical properties.

For example, chlorine and bromine belongs to same group and hence they have similar chemical properties.

Thus, we can conclude that two elements possess similar chemical properties as they will have same number of electrons in their valence shell.

i think that is new experiments yield untrustworthy data and should be carefully considered, because you don't know what will happen with the experiments.

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high