When solutions of sodium chloride are made for intravenous use, it must have a molarity of 0.155 M. When starting with a 5.00 L 1.00 M NaCl stock solution, how
many milliliters of the stock solution will be used to make 455 mL of the needed
solution?

beta decay is the answer

the atomic mass is the bottom number on the element.

-steel jelly

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.