Can someone explain what radioisotopes are?

A radioisotope is a radioactive isotope.

Explanation:

On the Periodic Table, elements 92 and up are radioactive. So that is Uranium and any higher elements. Remember that radioactive elements love to decay and are dangerous.

Isotopes are different forms of an element. For instance, we could have different amount of neutrons in the same element (same number of protons).

We could have an element like He - 4 vs. He - 6, where He - 4 would have 2 neutrons and He - 6 would have 4 neutrons.

So a radioisotope would be an elemental isotope that is radioactive. A good example of this is Uranium.

We have thousands of different isotopes of Uranium, but 2 are well known: Uranium - 235 and Uranium - 238. Both are the same element with the same amount of protons, but both have a different amount of neutrons.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

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.