Element a has seven valence electrons. how does its reactivity compare to that of element b, which has four valence electrons? element a is more reactive. element a is less reactive. element a and b have the same reactivity. element a has no reactivity

Element A is more reactive. Take Fluorine for example. Since its in group 17, it needs one more electron to have an octet. Compared with carbon, group 14 with 4 valence electrons, Fluorine wants and is able to get an electron much more easily.

The correct answer is option C.

Explanation:

The radioisotopes in the Earth's interior are not in pure form and exhibit various entrenched impurities and are interspersed. Thus, when a neutron is discharged by a decaying atom, its occurrences of hitting another atom of radioisotope in order to continue the chain reaction becomes lower in comparison to the man-made nuclear reactor. In this manner, the radioactive chain reaction in the interior of the Earth is not well-sustained.