Question

the shape of a molecule depends upon the number of reds at the central atom. each red repels one another and this explains why there is so much symmetry in nature. if there is no central atom, there are no reds, and the molecule is either individual atoms or ions, or a diatomic molecule. if there is a central atom, and the octet rule is not violated, there can be only 2, 3, or 4 reds. a red can be either a bond or just nonbonding electrons. double and triple bonds are treated as a single red. if we treat all reds the same, when there are 2 reds the bond angles are 180°, when there are 3 reds the bond angles are 120°, and when there are 4 reds the bond angles are 109.5°. consider carbon dioxide, co₂. the lewis structure has 2 double bonds. the number of reds is 1. the bond angles are 2° and the shape is 3. co₂ is a 4 symmetrical/asymmetrical molecule. a. 0 b. 1 c. 2 d. 3 e. 4 f. 180 g. 90 h. 120 i. 109.5 j. diatomic k. linear k. planar trigonal m. bent n. pyramidal o. tetrahedral p. symmetrical q. asymmetrical

Explanation:

• For the number of REDs: As per the text, double bonds are treated as a single RED. \(CO_2\) has 2 double bonds ( \(C = O\) bonds), so the number of REDs is 2.
• For the bond angles: When there are 2 REDs, bond angles are \(180^{\circ}\) (from the text description).
• For the shape: With 2 REDs and bond angles of \(180^{\circ}\), the molecular shape is linear.
• For symmetry: \(CO_2\) has a linear shape with two identical \(C = O\) bonds. The dipoles from the \(C = O\) bonds (due to electronegativity difference between \(C\) and \(O\)) cancel each other out (because of the linear and symmetrical arrangement), making it a symmetrical molecule.

Answer:

1. C. 2
2. F. 180
3. K. linear
4. P. symmetrical