Chemical Bonding

Which of the following statements describes why atoms form bonds?

• To attain a noble gas electronic configuration

• To ensure that element exists as compounds

• To ensure that all atoms have 8 electrons in their outermost shell

• To ensure that elements exist as molecules

Fluorine is a diatomic molecule. Fluorine is in Group 17. How many electrons are shared in this covalent bond?

Draw a 'dot and cross' diagram for oxygen gas.

Answer explanation

Draw a dot and cross diagram for carbon dioxide, showing only valence electrons.

Answer explanation

Draw a dot and cross diagram for ammonia.

Answer explanation

Sodium chloride is an ionic compound.

Which statement about sodium chloride is not correct?

• Sodium ions and chloride ions are oppositely charged.

• Sodium chloride has a high melting point.

• Sodium chloride solid conducts electricity.

• Sodium chloride solid exists as a lattice.

Answer explanation

Select the properties of simple covalent substances.

• Low melting and boiling points.

• High melting and boiling points.

• Do not conduct electricity.

• Good conductors of electricity.

Answer explanation

Which of the following properties could phosphorus trichloride, PCl₃, have?

• A

• B

• C

• D

Why do simple molecular substances have low melting and boiling points?

• The intermolecular forces between simple molecules are weak.

• The covalent bonds holding the atoms together in a simple molecule are strong. A large number of covalent bonds hold the atoms together in simple molecules.

Answer explanation