Principal shell shows the main energy level, in that there are some more energy levels. This is how the atomic structure is defined according to the Quantum Mechanical model of atom. So exactly why do subshells exist and all i don't know
Water deposits soil ,sediments ,and rock by moving them to a different place .Say like a beach .The ocean is currently moving the bits of sand and (glass:sand)rock pieces and always ending up in new places.Same as a river.!!!!
1.8 moles of oxygen atoms are present in 30.5 grams of hydrogen peroxide.
<u>Explanation:</u>
First we have to convert the given weight of hydrogen peroxide to molar mass of hydrogen peroxide. So for this, we have to divide the given weight with the molecular mass of hydrogen peroxide.

So,

Second step, in this moles, 2 molecules of oxygen are present. Thus 1 mole of Hydrogen peroxide consists of 2 moles of oxygen. Then,

So, 30.5 grams of hydrogen peroxide consists of 1.8 moles of oxygen.