Unit A Review

In an electron dot diagram of aluminum (Al), how many dots should be drawn around the element’s symbol?

• 1

• 2

• 3

• 4

• 5

Which of the following atoms is believed to contain three lone pairs of electrons?

• S

• P

• N

• Cl

According to modern theories, the number of bonding electrons in an atom of nitrogen is

• 1

• 3

• 5

• 7

Electronegativity can be defined as:

• The relative ability of an atom to attract electrons

• The energy change that occurs when an electron is accepted by an atom

• The amount of energy required to remove an electron from an atom

• The amount of energy required to separate neutrons and protons in an atom

• The total charge of an ion

The atom with the highest electronegativity is

• Li

• Be

• N

• F

Which pair of elements would form the most ionic bond?

• O and H

• O and F

• S and Cs

• S and Li

Based on the electronegativities K = 0.8, H = 2.1, Br = 2.8, which of the following statements is true?

• H₂, Br₂, and HBr are nonpolar covalent molecules.

• KBr is a nonpolar covalent compound and HBr is an ionic compound

• HBr is a nonpolar covalent compound and Br₂ is a polar covalent molecule

• H₂ is a nonpolar covalent molecule and HBr is a polar covalent molecule.

What is the electron dot diagram for the ion P^3-?

• 
• 
• 
• 

What is a double bond?

• a bond between two atoms

• one pair of electrons shared between two atoms

• two pairs of electrons shared between two atoms

• two pairs of electrons shared between four atoms

What is the central atom in NO₃

• O

• N

• 3

• None