IB Chemistry: S2.2 The Covalent Model

What is the purpose of Lewis structures in chemistry?

• To create 3D models of molecules

• To represent bonding between atoms and predict molecular properties.

• To calculate atomic mass

• To determine the state of matter

Tags

NGSS.HS-PS1-1

Explain the concept of VSEPR theory and how it helps in predicting the shape of molecules.

• VSEPR theory explains how the arrangement of electron pairs determines the shape of molecules based on minimizing repulsion between them.

• VSEPR theory is used to predict the color of molecules based on their shape.

• VSEPR theory is only applicable to inorganic molecules.

• VSEPR theory explains how the arrangement of protons determines the shape of molecules.

How does hybridization of atomic orbitals occur in covalent bonding?

• Atomic orbitals combine to form hybrid orbitals that are more suitable for bonding in a molecule.

• Hybridization occurs due to the transfer of electrons between atomic orbitals

• Atomic orbitals repel each other, preventing hybridization

• Hybrid orbitals are formed by the combination of electrons from different atoms

Discuss the significance of molecular polarity in determining the physical and chemical properties of compounds.

• Molecular polarity has no impact on compound properties

• Compounds with high molecular polarity are less likely to form bonds

• Molecular polarity plays a crucial role in determining the physical and chemical properties of compounds by influencing intermolecular forces and interactions.

• Physical and chemical properties are solely determined by molecular weight

Tags

NGSS.HS-PS2-6

Provide an example of a molecule with resonance structures and explain how resonance affects its stability.

• Benzene

• Methane

• Water

• Ethanol

Draw the Lewis structure for the molecule CH4 (methane) and determine its molecular geometry using VSEPR theory.

• Octahedral

• Tetrahedral

• Linear

• Trigonal planar

Identify the hybridization of the central atom in the molecule H2O (water) and explain how it influences the molecule's shape.

• sp3

• dsp3

• sp2

• sp

Compare the polarity of CO2 (carbon dioxide) and H2O (water) based on their molecular structures.

• CO2 is nonpolar, and H2O is polar.

• CO2 and H2O are both polar.

• CO2 and H2O are both nonpolar.

• CO2 is polar, and H2O is nonpolar.

Explain the concept of formal charge in relation to Lewis structures and its importance in determining the most stable resonance structure.

• Formal charge is only applicable to ionic compounds

• Formal charge is used to maximize charges on atoms

• Formal charge is irrelevant in determining resonance structures

• Formal charge is important in determining the most stable resonance structure by minimizing charges and placing negative charges on more electronegative atoms.

Describe the role of electronegativity in determining the polarity of covalent bonds within a molecule.

• Electronegativity determines the bond length in covalent bonds

• Electronegativity has no impact on covalent bond polarity

• Electronegativity determines the polarity of covalent bonds by influencing how the shared electrons are distributed between the atoms involved.

• Electronegativity affects the strength of ionic bonds