In the Earth's crust, the most common elements are:    Oxygen 46.1%   Silicon 28.2%   Aluminum 8.23%   Iron 5.63%   Calcium 4.15%   Sodium 2.36%  …  Magnesium 2.33%   Potassium 2.09%   Titanium 0.565%   Hydrogen 0.14%   In the atmosphere, the most common elements are Nitrogen and  Oxygen.he most common gas in the earth's atmosphere is in fact, nitrogen, with it making up 78% of the air you're breathing right now. However, oxygen does make up 21% of the air. + 57 others found this useful.