( ( ( atomic ( weight ( The weight ) ) ) ( of ( an atom ) ) ) ( ( determined ( by ( adding ( ( the number ) ( of ( ( ( protons and ) neutrons ) ( -LRB- ( ( ( ( the mass ) ( of electrons ) ) ( ( is usually ) ( considered ( to ( be negligible ) ) ) ) ) -RRB- ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ atomic) (NN weight) (NX (DT The) (NN weight))) (PP (IN of) (NP (DT an) (NN atom)))) (VP (VBN determined) (PP (IN by) (S (VP (VBG adding) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS protons) (CC and) (NNS neutrons)) (PRN (-LRB- -LRB-) (S (NP (NP (DT the) (NN mass)) (PP (IN of) (NP (NNS electrons)))) (VP (VBZ is) (ADVP (RB usually)) (VP (VBN considered) (S (VP (TO to) (VP (VB be) (ADJP (JJ negligible)))))))) (-RRB- -RRB-))))))))) (. .)))
atomic weight The weight of an atom determined by adding the number of protons and neutrons (the mass of electrons is usually considered to be negligible).
(ROOT (S (S (VP (TO To) (VP (VB determine) (NP (NP (DT the) (JJ atomic) (NN weight)) (PP (IN of) (NP (DT an) (NN element))))))) (, ,) (NP (PRP you)) (VP (MD should) (VP (VB add) (PRT (RP up)) (NP (NNS protons) (CC and) (NNS neutrons)))) (. .)))