First off chlorine is not a metal so you can ignore that one.
Sodium and Rubidium are in group 1 of the periodic table and Magnesium is in group 2.
Group one metals are more reactive than group two because it is harder for the group two metals to lose their 2 valence (outer most) electrons.
As you go down group 1 there is an increase in the reactivity this is because as you go down there is an increase in the atomic radius which leads to more shielding. This weakens the electrostatic forces of attraction making it easier to lose the outermost electrons, therefore they are more reactive.
<u>Answer:</u>
<em>Atomic number 75 is dedicated to an element named rhenium and has been given Re as its chemical name.</em>
<u>Explanation:</u>
With a really low concentration it is one of the rarest metals that is found in Earth's crust.
Like all other elements rhenium also has certain isotopes among with 185 and 187 are the most stable ones. Hence these two are the ones that are naturally available abundance is 34% and 63% respectively.
Molecules may be similar or different on the basis of size, shape, structure and chemical composition.
<h2>Similarities and differences</h2>
Two molecules can be considered similar or different on the basis of size, shape, structure and chemical composition. The molecules in the two proposed systems are consider the same when they are similar in size, shapes, structure and chemical composition.
While on the other hand, the molecules is considered different when they have different structure and chemical composition so we can say that molecules may be similar or different on the basis of size, shape, structure and chemical composition.
Learn more about molecules here: brainly.com/question/26044300
Learn more: brainly.com/question/26268787
