ANSWER
Sr2+, Se2-, Br-
EXPLANATION
The first ion is a strontium ion
The atomic number of strontium is 38, this implies that the number of electrons is 38
Sr2+ means strontium has loses two electrons in order to attain it octet configuration. Sr2+ has the configuration of krypton and krypton is a noble gas
Ti2+
Titanium has an atomic number of 22, this implies that the number of electrons is 22.
Ti2+ means titanium has loses two electrons. When it loses two electrons, it will attain the configuration of calcium. Calcium is a group 2 metal and it is not a noble gas.
Se2-
Selenium has an atomic number of 34, this implies that the number of electrons is 34
Se2- means selenium has gained two electrons. When it gained two electrons, the number of electrons become 36. Se2- has the configuration of krypton.
Ni2+ has the configuration of zinc
Br- has the configuration of Krypton
Mn3+ has the configuration of titanium
Hence, the ions with noble gas configuration are
Sr2+, Se2-, Br-
