Impatiens is of course Latin for impatient and alludes to the explosive nature of the seedpods. Balsaminaceae is named after the type Impatiens balsamina and I think this comes from the sappy residue of the stems. Impatiens balsamina in the wild has different flowers the wild type is kind of rare now days. The side petals are much shorter then the ones found most often in cultivation. The author of the name for Impatiens and Balsaminaceae is Linnaeus. At the time there were only 7 species known in 1753 even though some had been grow since the late 1500s.