Why might organizing elements based on their atomic masses and their properties not be the best way to organize in a periodic table?

1 Answer
Dec 8, 2017

Atomic masses can be very similar between atoms yet the atoms themselves can show very different chemical properties.

Explanation:

For example; Argon (Ar) has a similar relative atomic mass (39.948) to Potassium (K) (39.08). Argon is a noble gas that is chemically inert - this means VERY unreactive. Potassium, however, is very reactive and does not behave like Argon....at all.

More important to chemical reactivity and properties is electron count and valency (how many outermost electrons an atom has), this can be observed by the group number of an atom in the periodic table.