An atom has 24 protons, 22 electrons, and 28 neutrons. What is the MASS # of the atom

What metric units would you use to measure the thickness of a key

Which of these is a physical property

If it is an isoelectronic series select true, if not select false. o2-, s2-, se2-, te2- na+, k+, rb+, cs+ n3-, p3-, as3-, sb3- ag, cd+, sn3+, sb4+ f-, cl-, br-, i- f-, ne, na+, mg2+ s2-, s, s6+