11. Calculate the mass collision stopping powers for an electron and for a positron with a kinetic energy of 50 MeV in aluminum. (Include the polarization-effect correct ion.)

Efficiency is an action of doing something. for example when you take a test. good efficiency means you did well but bad effeciency or no effiency means you did bad.

It won't lose or gain electrons if it's a covalent bond it shares the electrons with another atom or atoms. if it is an ionic bond it will lose the 3 electrons on the outer shell and become a positively charged ion.  credit goes to @sunshinebaby of answers.yahoo.com.

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