Entrance Exam_Chem_Atomic Structure and Chemical Bonds

Based on the information in the table, which of the following arranges the bonds in order of decreasing polarity?

• Cl–F > H–I > Se–N

• Se–N > H–I > Cl–F

• Cl–F > Se–N > H–I

• H–I > Se–N > Cl–F

Which of the following correctly shows the bond polarity?

• 
• 
• 
• 

Which of the following best predicts the type of bond that forms between Br and Br?

• Polar covalent

• Nonpolar covalent

• Ionic

• Metallic

Which of the following bonds is likely to have the most ionic character?

• Ca–S

• P–Cl

• Si–S

• K–Cl

 Which of the following bonds is likely to have the most ionic character?

• N–F

• Na–F

• Mg–O

• C–O

Which of the following best predicts the type of bond that forms between Cs and Cl?

• Nonpolar covalent

• Polar covalent

• Ionic

• Metallic

Which of the following correctly shows the bond polarity?

• 
• 
• 
• 

In which of the following ionic compounds is the force of attraction between cation and anion the strongest?

• RbI

• CsI

• MgO

• SrS

The energy required to separate the ions in a CsF crystal lattice into individual Cs⁺(g) and F^-(g) ions is known as the lattice energy of CsF(s). As shown in the table below, the lattice energy of CsF(s) is smaller than the lattice energy of a similar compound, KF(s).

Which of the following best explains why the lattice energy of CsF  is smaller than the lattice energy of KF?

• Cs⁺ has a larger ionic radius than K⁺, so the distance between cation and anion is greater in CsF than in KF.

• Cesium has a smaller first ionization energy than potassium, so less energy is required to form the Cs⁺ ion than to form the K⁺ ion.

• Cesium and fluorine have a greater electronegativity difference than potassium and fluorine, so the Cs–F bond is more polar than the K–F bond.

• Cs⁺ contains more core electrons than K⁺, so the valence electrons in Cs⁺ are more shielded from the nucleus than the valence electrons in K⁺.

The Lewis structure of I₂ is shown below.

Which of the following compounds has a Lewis structure that is electronically identical to that of I₂?

• HCl

• CO

• N₂

• BrF