(2) Elements with the same number of electrons in the outermost layer have similar chemical properties. Known atoms are element 16 and S atom. According to the drawing method of atomic structure diagram, x = 6；; m = 16；
(3) The most abundant element in organisms is oxygen; It is easy to get two electrons in a chemical reaction. The ion symbol formed is O2-;
So the answer is: (1) 9.0438+02; Sodium, magnesium and aluminum;
(2)6; 16;
(3) oxygen; Oxygen.
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