At room temperature, chlorine is a gas, bromine is a liquid, and
iodine is a solid. However, all
three elements share some
physical properties. They also
have very similar chemical
properties. They are grouped in the same column on the periodic table. What common property do
you observe?

An electric power distributor charges residential customers $0.10 per kilowatt-hour (kwh). the company advertises that "green power" is available in 150 kwh blocks for an additional $4 per month. (green power is generated from solar, wind power, and methane sources.) if a certain customer uses an average of 391 kwh per month and commits to one monthly 150 kwh block of green power, what is her annual power bill