What are valence electrons (be specific)?

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h

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?

If a straight-chain hydrocarbon is a gas at room temperature, how many carbon atoms will it have? a. 6 carbon atoms b. 12 carbon atoms c. 24 carbon atoms d. 3 carbon atoms