( ( ( ( ( ( A ( lithium-7 atom ) ) ( contains ( ( ( ( ( ( three protons ) , ) ( four neutrons ) ) , ) and ) ( three electrons ) ) ) ) , ) and ) ( it ( is ( ( ( a boson ) , ) ( which ( means ( that ( ( its ( total ( atomic spin ) ) ) ( is ( ( ( ( an integer ) , ) usually ) zero ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT A) (JJ lithium-7) (NN atom)) (VP (VBZ contains) (NP (NP (CD three) (NNS protons)) (, ,) (NP (CD four) (NNS neutrons)) (, ,) (CC and) (NP (CD three) (NNS electrons))))) (, ,) (CC and) (S (NP (PRP it)) (VP (VBZ is) (NP (NP (DT a) (NN boson)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ means) (SBAR (IN that) (S (NP (PRP$ its) (JJ total) (JJ atomic) (NN spin)) (VP (VBZ is) (NP (NP (DT an) (NN integer)) (, ,) (RB usually) (NP (CD zero)))))))))))) (. .)))
A lithium-7 atom contains three protons, four neutrons, and three electrons, and it is a boson, which means that its total atomic spin is an integer, usually zero.
(ROOT (S (NP (NNP Lithium)) (VP (VBZ has) (NP (CD three) (NNS electrons))) (. .)))