The number of s-electrons present in an ion with 55 protons in its

ion55The VacIon Plus 55 pump is a 55 Ls ion pump regularly used in general-purpose ultrahh and extreme hh vacuum systems for evacuating electron devices, sensitive electronIron-55 (55 Fe) is a radioactive isotope of iron with a nucleus containing 26 protons and 29 neutrons.It decays by electron capture to manganese-55 and this process has a half-life of