what's the geometry of methyl radical?
trigonal pyramidal or quasi-trigonal planar?
for A levels, we draw trigonal pyramidal and write bond angle
more than 109.5° or between 109.5 and 107.5° ?
If CF3 radical, then trigonal pyramidal. If CH3 radical, then
trigonal planar. Reasons for the difference are beyond the H2
syllabus (a hint for A grade students : ask yourself what
possible thermodynamic advantage could a CH3 radical gain by
adopting sp2 hybridization, versus what possible thermodynamic
advantage could a CF3 radical gain by adopting sp3 hybridization,
taking into consideration the contrasting natures of s and p
orbitals), go ask your school teacher or private tutor if
you're interested.
Cambridge is reasonable. As long as you give chemically
reasonable justifications for your answer, Cambridge (in most
cases) will accept a variety of reasonable answers (eg. a range for
bond angles, explanation & justification for either geometry
for either radical), especially for beyond-syllabus questions such
as these.
