C. Not each element has a known neutron number
Answer: With the exception of hydrogen, all atoms have three main parts. The parts of an atom are protons, electrons, and neutrons. A proton is positively charged and is located in the center or nucleus of the atom. Electrons are negatively charged and are located in rings or orbits spinning around the nucleus.
Explanation:
The standard temperature is 0c.
the standard pressure is 1atm.
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