What is the frequency of light produced by the electronic transition between levels 4 and 2 of a hydrogen atom

For each of the compounds below, show that the charges on the ions add up to zero. a. kbr b. cao c. li(2)o d. cacl(2) e. alcl(3)

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.

How many grams are in 68.2 molecules of br2?