Cl- and Ca2+ has the electronic configuration of the noble gas, Ar, with 18 electrons.
The stable ions of all the elements except the Transition metals, Actinide, and Lanthanide series (that is the d and f block elements) form stable ions that are isoelectronic to a nobel gas by gaining or losing electrons in order to achieve an s2 p6 stable octet. For example, sodium will lose one electron to have the same electron configuration as neon, while nitrogen will gain three electrons to become isoelectronic to neon.
Neon
Potassium must lose one electron (to have the same configuration as the noble gas argon), and fluorine must gain one electron (to have the same configuration as neon)
neon
Potassium and chlorine are the only two that can.
The stable ions of all the elements except the Transition metals, Actinide, and Lanthanide series (that is the d and f block elements) form stable ions that are isoelectronic to a nobel gas by gaining or losing electrons in order to achieve an s2 p6 stable octet. For example, sodium will lose one electron to have the same electron configuration as neon, while nitrogen will gain three electrons to become isoelectronic to neon.
The ions of elements nitrogen (N3-), oxygen (O2-), and fluorine (F-) will have the same electron configuration as a sodium ion (Na+), which is the same as the electron configuration of the noble gas neon.
Because each of them can form a cation with the electron configuration of a noble gas by donating one electron to another element.
Neon
Potassium must lose one electron (to have the same configuration as the noble gas argon), and fluorine must gain one electron (to have the same configuration as neon)
N3- , O2- , F- , Na+ , Mg2+ , Al3+ all have the same electron configuration as Neon.
neon
Potassium and chlorine are the only two that can.
argon
[Ar]3d104s24p6
There is no such noble gas with the same electron configuration as helium ion. Helium is the first noble gas, is stable and does not form ions. There can be, however, other ions such as H- or Li+ that will have the same number of electrons as element helium.
There is no noble gas with the same electronic configuration as the element barium (Ba). But Ba2+ ion and the noble gas xenon (Xe) will have the same number of electrons (54 electrons each).