Look at the diagram below. A buret filled with a base of known concentration is set up on a stand with a stopcock to drip into a flask containing acid of an unknown concentration. A small container of phenolphthalein is nearby. Which best describes what is taking place in the diagram? The calibration of an acid is being completed with a base. A direct measurement of pH is taking place. An indirect measurement of pH is taking place. The final volume of an acid or base is being measured.

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.

alchemy hadn't scientific methods of study, appeal to mysticism and fantasy, the knowledge of chemistry and physics were modest at that time.

alchemy was - but as new rules were discovered it either changed into chemistry or it became "unscientific".