yes
The Sulfide ion, S2-, is isoelectronic with Cl-
I do not think that Bromine behaves like Krypton in chemical reactions. Krypton is very unreactive due to the fact that it has a full stable set of valence electrons, and Bromine is extremly reactive and has high electronegativity because is does not have a full stable set of valence electrons. Although, I do suppose that if a Bromine atom were to become a negative ion (Br+1) by gaining another electron, it would act as if it were a Krypton atom.
No. The K+ ion forms because it is isoelectronic with argon.
If bromine gains one more electron, then it will have 36 electrons total. The only neutral atom with 36 electrons is just the next element on the periodic table, Krypton.
The Hydride ion (H-) and the lithium ion (Li+).
no
Bromide ion is isoelectronic with Krypton.
Krypton and selenide ion are isoelectronic with 36 electrons each
None. The Se2- ion is isoelectronic with Krypton.
The only elements that form an ion isoelectric with krypton are the elements in Period 4 and Columns 15 through 17 of a wide form periodic table and the elements in Period 5 and Columns 1 and 2 of a wide form periodic table. All other elements do not form such an ion.
Krypton and Selenide ion have 36 electrons and are isoelectronic
The noble gas krypton has the same electron configuration as an ion of bromine, Br-.
Neon is isoelectronic with the sodium ion.
The Sulfide ion, S2-, is isoelectronic with Cl-
oxide ion is isoelectronic with neon.
Argon is isoelectronic with the sulfide ion.
Oxide ion O2- is isoelectronic with neon.