Please solve this question

Elements that do not have full outer electron shells will donate, share, or take electrons from other atoms. choose the items that have the correct binary ionic formula.

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?

Apropane torch is lit inside a hot air balloon during preflight preparations to inflate the balloon. which condition of the gas remains constant