Answer: A) Na+ and O2-
Explanation:
To know the electronic configuration, one has to determine the numbers of electrons present in each atom.
Na+ means a sodium atom that has lost one valence electron. A Sodium atom initially has 11 electrons, but having lost an electron making it 10 electrons remaining with electron configuration of 1s2 2s2 2p6.
O2- means oxygen atom that has gained two valence electrons. An oxygen atom initially has 8 electrons, having gained two electrons makes it 10 electrons with electron configuration of 1s2 2s2 2p6. same as Na+
The purpose of gaining or losing electrons is to attain a stable duplet or octet structure.
