Adecrease in velocity over time a velocity b time c acceleration d deceleration

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

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?