In one mole, there are 6.022 x 10 23 atoms. Here's another way: there are 6.022 x 10 23 atoms of carbon in 12 grams of carbon-12. Let's say that real clearly: one mole of ANYTHING contains 6.022 x 10 23 entities. The word entities is simply a generic word.
Shadow zone. A seismic shadow zone is an area of the Earth's surface where seismographs cannot detect an earthquake after its seismic waves have passed through the Earth. When an earthquake occurs, seismic waves radiate out spherically from the earthquake's focus.
A rain shadow is a dry area on one side of a mountain or mountain range. This is usually the opposite side to a sea or other large body of water. The body of water provides moist air, and wind currents that head towards the mountains.