Helium is an odorless, colorless gas at room temperature. It is less dense than air. That's why helium balloons float. It is a non-reactive gas, a member of the Noble gas family. Its melting point is -272.2 oC and its boiling point is -268.93 o A chemical property of Helium is?

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.

Drug abuse will not lead to physical and psychological dependence. true or false ?

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons