Answer;
-(3) an atom in an excited state
Explanation;
-An electron in a sodium atom gains enough energy to move from the second shell to the third shell. The sodium atom becomes an atom in an excited state.
-Ground state is the lowest allowable energy state of an atom. When electrons are subjected to stimuli like heat, light or electricity an electron may jump to a higher energy level, which is the excited state. Excitation is the elevation in energy level above the baseline energy state.
The class can break or if you put it in cold water it can cool down down fast.
BaSO4 is the correct formula for barium (ll) sulfate