An astronomer has proposed a new theory about the evolution of the universe. what is the next step that the astronomer should take to make his theory reliable?

consensus on the theory from experimentation  

Explanation:

Once the astronomer has proposed a new theory, he must evaluate methods of experimentation that provide experiments that allow his theory to be confirmed or refuted.

These experiments can be defined as sets of procedures by means of which the astronomer will be able to propose a set of explanations for phenomena, constitution and formation of materials that are involved in his theory.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.