How many neutrons are in a ^15n isotope?

Which substances have the lowest melting points: ionic covalent, or metallic

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.

A40 kilogram skier starts at the top of a 12 meter high slope. at the bottom, she is travelling 10 meters per second. how much energy does she lose to friction