( ( that is ) ( , ( ( ( each ( silicon atom ) ) ( shares ( ( its ( four valence ) ) ( electronic ( with ( ( ( the ( four ( neighboring atoms ) ) ) , ) ( forming ( four ( covalent bonds ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (INTJ (DT that) (VBZ is)) (, ,) (S (NP (DT each) (NN silicon) (NN atom)) (VP (VBZ shares) (S (NP (PRP$ its) (CD four) (NN valence)) (ADJP (JJ electronic) (PP (IN with) (NP (NP (DT the) (CD four) (VBG neighboring) (NNS atoms)) (, ,) (VP (VBG forming) (NP (CD four) (JJ covalent) (NNS bonds))))))))) (. .)))
that is, each silicon atom shares its four valence electronic with the four neighboring atoms, forming four covalent bonds.
(ROOT (S (NP (NNP Valence)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (JJ covalent) (NNS bonds))))) (SBAR (S (NP (DT an) (NN atom)) (VP (MD can) (VP (VB form))))))) (. .)))
Valence is the term for the number of covalent bonds an atom can form.