How are the periods, or horizontal rows, on a periodic table ordered from left to right? (2 points) by similar state of matter. by increasing number of protons. by decreasing number of neutrons. by similar number of valence electrons.

Can someone me with questions 15 to 17 plz.

Carbon-14 undergoes radioactive decay in the reaction above. determine the type of radiation emitted in this reaction and describe what is happening to the nucleus during this reaction.

Which of the following statements is true about energy quantization at the atomic level? electrons in the outermost orbits are the most stable. electrons in all the orbits around the nucleus have the same amount of energy. electrons in the orbit closest to the nucleus have the least amount of energy. electrons absorb or release the same amount of energy independent of the energy levels.