15.How can a pure sample of barium sulphate be otained from barium carbonate?

What term describes technology that operates on an atomic level

Element before carbon on the periodic table

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?