Chemical Bonding Review

Which part of a lithium atom in the ground state is represented by the dots in its Lewis electron-dot diagram?

• the inner electrons that make up the kernel of the lithium atom
• the outermost electron in the second shell
• the valence protons in the nucleus
• the neutrons in the outer valence electron shell

Which of the following Lewis dot diagrams would represent an element in group 14. Write the letter in the space provided.

(a)  

Which of the following describes the energy changes that occur during a chemical reactions as chemical bonds are broken and formed?

• breaking bonds absorbs energy, whereas forming bonds releases energy
• breaking bonds releases energy, whereas forming bonds absorbs energy
• both the breaking and formation of bonds absorbs energy
• both the breaking and formation of bonds releases energy

How many electrons are shared between the atoms in a molecule of oxygen gas ( O₂ )?

• 2
• 3
• 4
• 5
• 6

Which of the following equations best represents the energy being absorbed as bonds are broken during a chemical reaction during a chemical reaction.

• Cl₂ → Cl + Cl + Energy
• Cl₂ + Energy → Cl + Cl
• Cl + Cl→ Cl₂ + Energy
• Cl + Cl + Energy→ Cl₂

An metallic atom (represented by letter X) has an oxidation state of +3 reacts with chlorine gas. Which of the following best represents the Lewis dot diagram for this compound?

• A
• B
• C
• D

In the formula XF₂, the element represented by X can be classified as a

• Group 1 metal
• Group 2 metal
• Group 1 nonmetal
• Group 2 nonmetal

When an atom of chlorine becomes and ion, which of the following takes place?

• Electrons are gained and the oxidation number increases.
• Electrons are gained and the oxidation number decreases.
• Electrons are lost and the oxidation number increases.
• Electrons are lost and the oxidation number decreases.

During a chemical reaction, which of the following occurs to an atom of sodium when it reacts with fluorine gas? Sodium...

• gains one electron and becomes a positively charged ion
• gains one electron and becomes a negatively charged ion
• loses one electron and becomes a positively charged ion
• loses one electron and becomes a negatively charged ion

What occurs when an atom of chlorine and an atom of hydrogen become a molecule of hydrogen chloride?

• A chemical bond is broken and energy is released.
• A chemical bond is broken and energy is absorbed.
• A chemical bond is formed and energy is released.
• A chemical bond is formed and energy is absorbed.