What is the state at room temperature of an element with atomic number 17

10. according to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants?

In which layer of earth do most earthauakes occur a_ inner core b_outer core c_mantle d_crust

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?