AP Chemistry 3rd Nine Weeks Review

Nitrogen will form which of the following ions?

• N
• N^-3
• N^-5
• N⁺⁵

Which of the following scientific claims about the bond in the molecular compound is HFmost likely to be true?

• There is a partial negative charge on the H atom.

• Electrons are shared equally between the H and F atoms.

• The bond is extremely weak.

• The bond is highly polar.

Which of the following compounds is most likely to be ionic?

• HBr

• MgCl₂

• CO₂

• CCl₄

Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound?

• It has the formula XZ₂

• It does not dissolve in water.

• It contains ionic bonds.

• It contains covalent bonds.

The elements C and Se have the same electronegativity value, 2.55. Which of the following claims about the compound that forms from C and Se is most likely to be true?

• The carbon-to-selenium bond is unstable.

• The carbon-to-selenium bond is nonpolar covalent.

• The compound has the empirical formula CSe.

• A molecule of the compound will have a partial negative charge on the carbon atom.

Has a central atom with less than an octet of electrons

• H₂O

• NH₃

• BH₃

• CH₄

• SiH₄

Has two lone pairs of electrons

• H₂O

• NH₃

• BH₃

• CH₄

• SiH₄

Of the following compounds, which is the most ionic?

• SiCl₄

• BrCl

• PCl₃

• Cl₂O

• CaCl₂

Of the following single bonds, which is the LEAST polar?

• N-H

• H-F

• O-F

• I-F

Resonance is most commonly used to describe the bonding in molecules of which of the following?

• CO₂

• O₃

• H₂O

• CH₄

• SF₆