What character of the actual elements (aluminum, silicon, oxygen) present in alumina and silica cause the stationary phase to be very polar?.

aluminum and silicon and the electronegative character of the oxygen.

Explanation:

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the atomic mass is the bottom number on the element.

-steel jelly

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.