O2- stands for superoxide anion, S2- stands for sulfide anion, H- stands for hydrogen anion, and Na+ stands for sodium this all ions possess the electron configuration of noble gas because each of them (O2-, S2-, H-, and Na+) has a full outer shell.
The answer would be modeling, because craving is when you take a block of something and slice it t make something,and casting is when you put layers over layers to form a something. so the answer will be modeling.
Dalton thought that atoms were indivisible particles. But Thomsons discovery of the electron proved that the subatomic particles exist.
