Which instrument, along with a telescope, allows study of the wavelengths of visible light coming from a star?

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?

How many absorptions would you expect to observe in the 13c nmr spectra of the following molecules? a) 3-chloropentane b) cis-4-methyl-2-pentene