( ( Because ( ( an atom ) ( ( is normally ) ( electrically neutral ) ) ) ) ( ( -- ( ( ( its ( positive ( and ( negative charges ) ) ) ) ( must balance ) ) -- ) ) ( it ( ( has ( ( an ( equal number ) ) ( of ( ( electrons and ) protons ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Because) (S (NP (DT an) (NN atom)) (VP (VBZ is) (ADVP (RB normally)) (ADJP (ADVP (RB electrically)) (JJ neutral))))) (PRN (: --) (S (NP (PRP$ its) (JJ positive) (CC and) (JJ negative) (NNS charges)) (VP (MD must) (VP (VB balance)))) (: --)) (NP (PRP it)) (VP (VBZ has) (NP (NP (DT an) (JJ equal) (NN number)) (PP (IN of) (NP (NNS electrons) (CC and) (NNS protons))))) (. .)))
Because an atom is normally electrically neutral--its positive and negative charges must balance--it has an equal number of electrons and protons.
(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))) (. .)))