A. Molecular Structure-bonding, shapes, electronic structures One of the more fundamental issues chemistry addresses is molecular structure, which means how the molecule's atoms are linked together by bonds and what the interatomic distances and angles are. Another component of structure analysis relates to what the electrons are doing in the molecule that is how the molecule' s orbitals are ocupied and in which electronic state the molecule exists. For example, in the arginine molecule shown in Fig. 5. 1, a HooC-carboxylic acid group(its oxygen atoms are shown in red) is linked to an adjacent carbon atom (yellow) which itself is bonded to an -NH amino group (whose nitrogen atom is blue). Also connected to the a-carbon atom are a chain of three methylene-CH2-groups, a-NH-group, then a carbon atom attached both by a double bond to an imine -NH group and to an amino-NH, group2 A. Molecular Structure- bonding, shapes, electronic structures One of the more fundamental issues chemistry addresses is molecular structure, which means how the molecule’s atoms are linked together by bonds and what the interatomic distances and angles are. Another component of structure analysis relates to what the electrons are doing in the molecule; that is, how the molecule’s orbitals are ocupied and in which electronic state the molecule exists. For example, in the arginine molecule shown in Fig. 5.1, a HOOC- carboxylic acid group (its oxygen atoms are shown in red) is linked to an adjacent carbon atom (yellow) which itself is bonded to an –NH2 amino group (whose nitrogen atom is blue). Also connected to the a-carbon atom are a chain of three methylene –CH2 - groups, a –NH- group, then a carbon atom attached both by a double bond to an imine –NH group and to an amino –NH2 group. 1.987