## Chemistry and Chemical Reactivity (9th Edition)

1 and 3: the central carbon is in trigonal planar geometry (3 bonding atoms, no lone pair) so the angle is approximately 120$^{\circ}$. 2: the carbon is in tetrahedral geometry this bond angle is approximately 109$^{\circ}$. 4 and 5: nitrogen is in trigonal pyramidal geometry and oxygen in bent geometry, both from the tetrahedral archetype (total of 4 bonding atoms and lone pairs), these bond angles are approximately 109$^{\circ}$. This chain is not linear because the first two carbons are in tetrahedral geometry and the last in trigonal planar.