Why do the Group I metals have a change of
positive one (+1)?

Explanation:

The +1 is their oxidation sate and this implies that the love to form bonds where they can lose one of their electrons.

The positive value indicates that an atom has lost an electron.

Group elements have one electron in their outermost shell. If they lose this one electron, they become isoelectric with the nearest noble gases and this imparts a stability on the atom.

So, group 1 elements have an oxidation state of +1

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa