Which of the following pairs of elements have the same valence electron configuration?

aluminum (Al) and argon (Ar)
arsenic (As) and gallium (Ga)
fluorine (F) and chlorine (Cl)
lithium (Li) and helium (He)

Astudent is trying to create a table that compares hypotheses, theories, and laws. hypothesis theory law do scientific researchers formulate it? yes yes yes does it explain why things happen? yes yes no yes yes yes is it used to make predictions? no yes yes which of the following questions would most likely fill the blank in the table? is it an intelligent guess? is it newly formulated? is it based on observations? has it been proved?

Estimate the molar mass of the gas that effuses at 1.6 times the effusion rate of carbon dioxide.

Astring vibrates with a frequency of 10 hz. why can't a person hear the sound waves produced by the vibrating string, no matter how large the amplitude of the waves? out! this is homework and due tomorrow! you so much!