( ( A ( mendelevium atom ) ) ( ( has ( ( ( 101 electrons ) , ) ( ( of which ) ( ( ( ( at least ) three ) ( -LRB- ( and ( perhaps ( four -RRB- ) ) ) ) ) ( can ( act ( as ( valence electrons ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN mendelevium) (NN atom)) (VP (VBZ has) (NP (NP (CD 101) (NNS electrons)) (, ,) (SBAR (WHPP (IN of) (WHNP (WDT which))) (S (NP (QP (IN at) (JJS least) (CD three)) (PRN (-LRB- -LRB-) (CC and) (RB perhaps) (NP (CD four)) (-RRB- -RRB-))) (VP (MD can) (VP (VB act) (PP (IN as) (NP (JJ valence) (NNS electrons))))))))) (. .)))
A mendelevium atom has 101 electrons, of which at least three (and perhaps four) can act as valence electrons.
(ROOT (S (NP (CD Four) (JJ valence) (NNS electrons)) (VP (MD can) (VP (VB be) (VP (VBN found) (PP (IN in) (NP (DT a) (NN carbon) (NN atom)))))) (. .)))