Look up at the atom on the periodic table of elements and find out what its atomic mass is. Subtract the number of protons from the atomic mass. This is the number of neutrons that the regular version of the atom has. If the number of neutrons in the given atom is different, than it is an isotope.

The answer is C, because isotopes are two or more of the same element with different atomic masses; so, in this case, the two chlorine atoms are the same molecules but they have different atomic masses, as the “35” and “37” say.

We breathe in oxygen and some of this carbon dioxide. When we exhale, we breathe out less oxygen but more carbon dioxide than we inhale. The carbon we breathe out as carbon dioxide comes from the carbon in the food we eat.

Although the oxide is O2– and is common, the O– anion will actually repel away another electron, so is more stable than O2–.

Please visit the Oxygen element page for information specific to the chemical element of the periodic table. Oxygen is a colorless, odorless and tasteless gas. It will support life.

O2 is made up of two atoms of oxygen found in nature because the atomic nascent oxygen is very unstable in nature and cannot exist independently. O2 is not a compound. It is a Molecular form of the Element Oxygen.

So, to reiterate, the difference between oxygen (O) and oxygen (O2) is that the former is an oxygen atom while the latter consists of two O atoms bound together, forming a molecule also called oxygen.

Tetraphosphorus pentasulfide | P4S5 – PubChem.

Phosphorus pentasulfide

Disilicon Hexabromide

Dinitrogen trioxide

BORON TRIFLUORIDE