One evening last summer, as I strolled along the promenade in Limbe, a small, scenic port town in southwestern Cameroon, I was stopped by a well-dressed young man who greeted me warmly and took me by the hand.
Phosphorus has 3 shells. The outer shell contains 5 electrons. The electronic configuration is :- <br /> 1s2, 2s2, 2p6, 3s2, 3p3.
If an atom of tin has a mass number of 118 and an atomic number of 50, how many neutrons are in its nucleus? 68 Most calcium atoms have an atomic number of 20 and a mass number of 49, but some calcium atoms have a mass number of 48. What word could you use to describe these two kinds of calcium atoms? Isotopes