Chemical Bonding review

What are the interactions formed and broken when magnesium sulfate dissolves in water?

• Hydrogen bonding formed; ionic bonds broken

• Ionic bonds formed; hydrogen bonding broken

• Ion-dipole attractions formed; ionic bonds and hydrogen bonding broken

• Permanent dipole-permanent dipole attractions formed; ionic bonds and hydrogen bonding broken

Which of the following correctly explains why bromine does not readily dissolve in water?

• The energy released when weak permanent dipole-permanent dipole attractions are formed between Br2 and H2O molecules is insufficient to compensate for the energy needed to overcome the stronger hydrogen bonding between H2O molecules

• The energy released when weak instantantaneous dipole-induced dipole attractions are formed between Br2 and H2O molecules is insufficient to compensate for the energy needed to overcome the stronger hydrogen bonding between H2O molecules

• The energy released when hydrogen bonds are formed between Br2 and H2O molecules is insufficient to compensate for the energy needed to overcome the stronger hydrogen bonding between H2O molecules

Which of the following descriptions of electrical conductivity is incorrect?

• Ionic compounds can conduct electricity in molten or aqueous state due to the presence of mobile ions

• Graphite can conduct electricity in solid state due to the presence of delocalised valence electrons

• Metals can conduct electricity in solid state due to the presence of mobile ions and electrons

• HCl can conduct electricity in aqueous solution due to the presence of mobile ions

How many  $\sigma$  and  $\pi$  bonds are present in this molecule? (count carefully)

• 8, 2

• 8, 4

• 10, 4

• 12, 2

Which of the following descriptions of bonds is incorrect?

• Ionic bonds are the electrostatic attraction between oppositely charged ions

• Metallic bonds are the electrostatic attraction between a lattice of positive ions and delocalised electrons

• Covalent bonds are the electrostatic attraction both within and between molecules

• Covalent bonds are the electrostatic attraction between a shared pair of electrons and positively charged nuclei

Which of the following shows the correct dot-and-cross diagram for Al₂Cl₆?

• 
• 
• 
• 

According to VSEPR theory, which is NOT a possible shape of a molecule with exactly 3 electron pairs around the central atom?

• Trigonal planar

• V-shaped

• Trigonal pyramidal

• Bent

According to VSEPR theory, what is the shape of SF₄? (make sure you know how to draw the dot-and-cross diagram)

• Square planar (6 bp, 2 lp)

• Trigonal bipyramidal (5 bp, 0 lp)

• Distorted tetrahedral (4 bp, 1 lp)

• Tetrahedral (4 bp, 0 lp)

Which of the following molecules is/are polar?

• HCl

• C₂H₄

• CO₂

• CH₄

• CO

What is the predominant intermolecular force of attraction in CHCl₃?

• Instantaneous dipole-induced dipole forces of attraction

• Permanent dipole-permanent dipole forces of attraction

• Hydrogen bonding

• Van der Waals' forces of attraction