Each covalent H bond is nonpolar.
A mole is mean the atomic number of 12 grams of carbon 12.
The answer is NH3 an NH4+.
Buffer solutions contain a weak base and its conjugate acid or a weak acid and its conjugate base. NH3 is a weak base and NH4+ is its conjugate acid.
The trend of atomic radius in the periodic table is increasing from right to left and from top to bottom. In reference to the table, oxygen has smaller radius compared to carbon, which is smaller than aluminum and which is also smaller than potassium. Thus, the trend from smallest to biggest is oxygen carbon, aluminum and potassium.
