How do you think Oxygen can be in the crust when it is a gas at room temperature in the atmosphere?

Through diffusion

Explanation:

Oxygen can be defined as the most abundant element on earth. It is a gas at room temperature. It becomes the part of the earth crust by the process of diffusion.

Diffusion is a process of movement of molecules from a region of high concentration to the low concentration. The oxygen remains in high concentration in the atmosphere diffuses into earth crust at low concentration.

a polar bond is formed when electrons are shared unevenly between atoms

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.