▁the ▁mole c ule ▁is ▁viewed ▁as ▁a ▁hydro gen ▁atom ▁bond ed ▁to ▁a ▁carbon ▁atom , ▁yield ing ▁the ▁name ▁" h yd rid oc ar bon ". ▁▁▁ ▁By ▁default , ▁these ▁names ▁pay ▁no ▁regard ▁to ▁the ▁exc itation ▁state ▁of ▁the ▁mole c ule . ▁When ▁that ▁attribute ▁is ▁considered , ▁the ▁states ▁with ▁one ▁un pa ired ▁electron ▁are ▁named ▁" m eth y ly l id ene " ▁or ▁" h yd rid oc ar bon ( • )", ▁whereas ▁the ▁excited ▁states ▁with ▁three ▁un pa ired ▁electrons ▁are ▁named ▁" m eth an et ri yl " ▁or ▁" h yd rid oc ar bon ( 3 • ) ". ▁ ▁Bond ing ▁ ▁As ▁an ▁odd - elect ron ▁species , ▁CH ▁is ▁a ▁radical . ▁The ▁ground ▁state ▁is ▁a ▁double t ▁( X 2 Π ). ▁ ▁The ▁first ▁two ▁excited ▁states ▁are ▁a ▁quart et ▁( with ▁three ▁un pa ired ▁electrons ) ▁ ▁( a 4 Σ − ) ▁and ▁a ▁double t ▁( A 2 Δ ). ▁The ▁quart et ▁lies ▁at ▁ 7 1 ▁k J / m ol ▁above ▁the ▁ground ▁state . ▁▁ ▁Re actions ▁of ▁the ▁double t ▁radical ▁with ▁non - rad ical ▁species ▁involves ▁insert ion ▁or ▁addition : ▁[ CH ] • ( X 2 Π ) ▁+ ▁ ▁→ ▁[ CH O ] • ▁+ ▁ ▁or ▁• ▁whereas ▁re actions ▁of ▁the ▁quart et ▁radical ▁generally ▁involves ▁only ▁abstra