There is a subtle difference between these two verses which doesn’t translate in the English. When describing an atoms weight of good, the words (ذَرَّةٍ خَيْرًۭا) have no ghunnah (i.e. stretch) between them, requiring the reader to continue without elongating the word. In the following verse, Allah ﷻ repeats a similar phrase but this time describing an atoms weight of sin: (ذَرَّةٍۢ شَرًّۭا). This time, a ghunnah is found between the two words, requiring a reciter to stretch the end of the first word for 2 moments before continuing with the rest of the verse.