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 shadow zone occurs because the density of the earth does not increase or decrease gradually with depth all the way to the center. What causes P wave shadow zones to form. P wave - when the p wave does not register because it is a certain degree away from the epicenter 103-143 degrees from the epicenter.