NSES Content Standard B  Physical Science: Structure and properties of matter Grades 9-12, page 178 Atoms interact with one another by transferring or sharing electrons that are furthest from the nucleus. These outer electrons govern the chemical properties of the element.

 
Benchmark 4D The Physical Setting: Structure of Matter
Grades 9-12, page 80
Atoms are made of a positive nucleus surrounded by negative electrons. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons.