Answer:
14 Hydrogen is a very reactive gas, and the alkali metals are even more reactive. In fact, they are the most reactive metals and, along with the elements in group 17, are the most reactive of all elements.
15 The halogen group of elements is the most reactive of the nonmetals. It is also the most reactive group of all chemical elements. Fluorine is the most reactive element in this group. Halogens are highly reactive because they are all electronegative.
16 Group 8A — The Noble or Inert Gases. Group 8A (or VIIIA) of the periodic table are the noble gases or inert gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.
17 Group 1: Alkali Metals
Group 1 elements are called alkali metals because of their ability to displace H2(g) from water and create a basic solution. Alkali metals are also known to react violently and explosively with water.
