Which principal energy level can hold a maximum of 18 electrons?

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?

In which situation can a mixture always be called a solution

Categorize them by metal, nonmetal, in periodic tableductilenon-ductilemalleableoften gain electrons easilygood conductorpoor conductorcan be liquidselements