The chemical combination of two or more different atoms in fixed amounts is called a(n)
a. orbit.
b. compound.
c. mixture.
d. element.

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?