( ( A ( neutral atom ) ) ( ( ( has ( ( an ( equal number ) ) ( of ( ( protons and ) electrons ) ) ) ) ( so ( that ( ( the ( ( ( positive and ) negative ) charges ) ) ( exactly balance ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ neutral) (NN atom)) (VP (VBZ has) (NP (NP (DT an) (JJ equal) (NN number)) (PP (IN of) (NP (NNS protons) (CC and) (NNS electrons)))) (SBAR (RB so) (IN that) (S (NP (DT the) (ADJP (JJ positive) (CC and) (JJ negative)) (NNS charges)) (ADVP (RB exactly)) (VP (VB balance))))) (. .)))
A neutral atom has an equal number of protons and electrons so that the positive and negative charges exactly balance.
(ROOT (S (SBAR (IN Because) (S (NP (NNS atoms)) (VP (VBP have) (NP (NP (JJ equal) (NNS numbers)) (PP (IN of) (NP (NP (JJ positive) (NNS protons)) (CC and) (NP (JJ negative) (NNS electrons)))))))) (, ,) (NP (PRP they)) (VP (VBP possess) (NP (DT a) (JJ neutral) (NN charge))) (. .)))