<span>During cardiopulmonary resuscitation (CPR), it is important to place the compression hands over the sternal body but not over the xiphoid process so that there is little risk of physically damaging the heart. By avoiding the xiphoid process, you will avoid hurting the heart of the person you are doing the CPR to. So make sure that your hands are only on the sternal body, and not the xiphoid process. </span>
Because the mass contributed by electrons is dwarfed by the nuclear contribution. There exists three orders of magnitude difference. Electronic mass can be ignored to a first approximation.
