La hipótesis de una investigación, se evalúa si es verdadera o falsa, en la etapa de: 1 Conclusión
2Observación
3Modelos y teorías
4Experimentación​

answer; /// i do believe that the correct answer is (a) boiling

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.