Question

1. choose the best answer.

two elements have an electronegativity difference of 2.1. what type of bond will form between them?
ionic
nonpolar covalent
polar covalent

1. choose all that apply.

the crystalline lattice structure of ionic compounds gives them which three properties?
malleability
brittleness
high melting points
strong bonds

Explanation:

Question 20

To determine the bond type from electronegativity difference:

• Nonpolar covalent bonds have an electronegativity difference close to 0 (usually < 0.5).
• Polar covalent bonds have a difference between ~0.5 and ~1.7 - 2.0 (varies by source, but 2.1 is often the threshold for ionic).
• Ionic bonds form when the electronegativity difference is ≥ 2.0 - 2.1 (depending on the scale). With a difference of 2.1, the bond is ionic.

• Brittleness: Ionic compounds are brittle; when stress is applied, like - charged ions align with like - charged ions, causing repulsion and breaking the lattice.
• High melting points: The strong electrostatic forces between ions in the lattice require a large amount of energy to overcome, leading to high melting points.
• Strong bonds: The ionic lattice has strong electrostatic attractions between oppositely charged ions.
• Malleability is a property of metals (due to mobile electron sea and ability to slide layers), not ionic compounds. So the three properties are brittleness, high melting points, and strong bonds.

Answer:

A. ionic

Question 21