Which of the following is not a polyatomic ion? a) no3-
b) caco3
c) c2h3o2-
d) c6h5coo-

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?

Select the statement that describe chemical properties a. antacid tablets neutralize stomach acid b. helium is the lightest monatomic element c. water freezes at 0 celsius d. mercury is liquid at room temperature

Which of the following is not a characteristic of a hydrogen bond? 1. it is responsible for the unusual physical properties of water. 2. it is weaker than a covalent bond. 3. it is stronger than other dipole-dipole interactions. 4. it can occur when hydrogen is covalently bound to very electronegative elements liks f, cl, br and i.