Which of the following elements matches the criteria below?

1. has 3 energy levels

2. found in group 7a

a. f

b. cl

c. ar

d. mn

Why is nh3 classified as a polar molecule

Using data from seismic waves, geologists have learned that earth’s interior is made up of several

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.