Shure what you need help with
The atomic mass of element is the weighted average atomic mass of the element with respect to the abundance of the isotopes of that element
atomic mass is the sum of the products of the mass of isotopes by their percentage abundance
atomic mass = 15.000 amu x 5.000 % + 16.000 amu x 95.000 %
= 0.7500 + 15.200
atomic mass of element is therefore 15.950
Ionic bonds are formed due to tendency of a metal to donate an electron and tendency of non metal to gain an electron.
The Cascades rain shadow can be described as such: ocean-influenced moist air masses are forced to rise when they meet the tall moun- tains. The rising air cools, condenses, and the moisture falls as precipitation. On the leeward (dry) side of the mountain, the now dry air warms and sinks.
C) Nucleus...... Hope it helps, Have a nice day :)