How is surface water naturally purified? freezing water destroys impurities

evaporation leaves impurities behind

sediments precipitate out

soil filters the water

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.