A. Oxygen. Oxygen has an atomic mass of 16. The atomic mass of an atom is the combined weight o the protons and neutrons. Since Oxygen's atomic mass is 16, it has 8 protons and 8 neutrons.
B is gas
The chemical element krypton is classed as a noble gas and a nonmetal.
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The two most abundant elements in Earths core are Iron and Nickel.
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Answer:A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name. Precipitation reactions can help determine the presence of various ions in solution.
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