Why are deposits of pure sodium metal or pure potassium metal not seen in nature

Three alkali metals in group 1 are a. calcium, strontium, barium b. boron, aluminum, gallium c. sodium, potassium, rubidium d. fluorine, iodine, chlorine

Water's surface tension and heat storage capacity are accounted for by its a) orbitals b) weight c) hydrogen bonds d) mass e) size

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?