How did Mendeleev arrange the elements in the first periodic table? In order of increasing atomic mass. In order of decreasing atomic mass. In order of increasing melting points and densities. In order of increasing atomic number.

It is important to wear proper protective equipment in lab even when not actively performing experiments because accidents can affect any researcher, even one not working on an experiment. select the best answer from the choices provided

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?