Why can a radioactive material affect photographic film even though the film is well wrapped in black paper?

According to the vsepr theory what is the shape of a molecule that has a central atom valence three other items with no lone pairs of electrons

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.

What type of matter is made of only one kind of atom