<span>the following element that is most reactive </span>would be Fluorine
In thermal cracking, high temperatures (typically in the range of 450°C to 750°C) and pressures (up to about 70 atmospheres) are used to break the large hydrocarbons into smaller ones. Thermal cracking gives mixtures of products containing high proportions of hydrocarbons with double bonds - alkenes.
When two atoms of the same element are covalently bonded, the radius of each atom will be half the distance between the two nuclei because they equally attract the electrons. The reason for this trend is that the bigger the radii, the further the distance between the two nuclei. Hope this helps:)
Answer:
There are 16 protons, 18 electrons and 16 neutrons. I hope this helped:)