Sucrose has the chemical formula CiaH20
a. Draw the Lewis Dot Structure
b. Determine the number of sigma and pi bonds
c. Determine the hybridization and molecular shape or every non-terminal atom
The Correct Answer and Explanation is :
It seems there was a typographical error in the molecular formula of sucrose. The correct formula for sucrose is C12H22O11, not “CiaH20.” Let’s break down the steps to answer your question regarding sucrose:
a. Lewis Dot Structure
To draw the Lewis Dot Structure for sucrose, we will need to follow these steps:
- Count the total number of valence electrons:
- Carbon (C) has 4 valence electrons.
- Hydrogen (H) has 1 valence electron.
- Oxygen (O) has 6 valence electrons.
The total number of valence electrons is calculated as:
(12 × 4) + (22 × 1) + (11 × 6) = 48 + 22 + 66 = 136 valence electrons.
- Arrange the atoms:
- Carbon atoms (C) form the backbone of the molecule, and hydrogen atoms (H) are attached to the carbons.
- Oxygen atoms (O) are attached to the carbons as well and typically form single or double bonds.
- Place electrons around atoms to satisfy the octet rule.
- Make sure each oxygen has 8 electrons in its valence shell, each carbon typically has 8 electrons (except those bonded to hydrogen), and hydrogen has 2 electrons.
Given the complexity of sucrose, it consists of two glucose molecules connected through an oxygen atom in the form of a glycosidic bond.
b. Number of Sigma and Pi Bonds
- Sigma bonds are single bonds formed by the overlap of orbitals directly between two atoms.
- Pi bonds are formed when orbitals overlap above and below the plane of the bonding atoms, typically in double and triple bonds.
For sucrose:
- The molecule has many single bonds between carbons, hydrogens, and oxygens (C-H, C-C, C-O).
- The only double bonds in sucrose are likely between carbon and oxygen atoms (C=O).
To determine the exact number of sigma and pi bonds, count all the single bonds (sigma bonds) and double bonds (one sigma and one pi bond).
c. Hybridization and Molecular Shape
Each non-terminal atom in sucrose undergoes sp3 hybridization because they are involved in single bonds, making them tetrahedral. Specifically:
- Carbon atoms bonded to other carbons and hydrogens are sp3 hybridized with a tetrahedral molecular shape.
- Oxygen atoms are also sp3 hybridized, but they have lone pairs, leading to a bent or angular shape at the oxygen.
For more complex bonding, like the glycosidic link between glucose units, some oxygen atoms may be involved in a sp2 hybridization if they are part of a double bond.
Sucrose’s 3D structure involves both sp2 and sp3 hybridized atoms, leading to a variety of bond angles and shapes.