( Xenon ( ( is ( ( ( ( an ( `` ( inert ( '' element ) ) ) ) , ) ( which ( means ( it ( ( does n't ) ( ( combine ( with ( other elements ) ) ) easily ) ) ) ) ) ) ( -LRB- ( ( if ( at all ) ) -RRB- ) ) ) ) . ) )
(ROOT (S (NP (NNP Xenon)) (VP (VBZ is) (NP (NP (NP (DT an) (`` ``) (JJ inert) ('' '') (NN element)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ means) (SBAR (S (NP (PRP it)) (VP (VBZ does) (RB n't) (VP (VB combine) (PP (IN with) (NP (JJ other) (NNS elements))) (ADVP (RB easily)))))))))) (PRN (-LRB- -LRB-) (FRAG (IN if) (ADVP (IN at) (DT all))) (-RRB- -RRB-)))) (. .)))
Xenon is an &quot;inert&quot; element, which means it doesn't combine with other elements easily (if at all).
(ROOT (S (NP (JJ Reactive) (NNS elements)) (VP (VBP are) (ADJP (JJ able) (S (VP (TO to) (VP (VB combine) (ADVP (RBR more) (RB easily)) (PP (IN with) (NP (JJ other) (NNS elements)))))))) (. .)))