CHEMICAL BONDING CONCEPT TESTPART AThis part consists of the questions that examine your knowledge ofchemical bonding. Each question has two parts: a response section in which you are asked to mark only one of two possible answers; a reason section in which you are asked to select the reason which explains the answer in the previous part of the question. On the answer sheet, please circle one answer from both the response and reason sections of each question.

1. At room temperature, sodium chloride, NaCl, exits as a molecule(1) True (2) FalsebecauseA) The sodium atom shares a pair of electrons with the chlorine atom to form a simple molecule.B) After donating its valance electron to the chlorine atom, the sodium ion forms a molecule with the chloride ion.C) Sodium chloride exists as a lattice consisting of sodium ions and chloride ions.D) Sodium chloride exists as a lattice consisting of covalently bonded sodium and chlorine atoms.2. Water (H2O) and hydrogen sulphide (H2S) have similar chemical formulas and structures. At room temperature, water is a liquid and hydrogen sulphide is a gas. This difference in state is due to(1) forces between molecules (2) forces within moleculesbecauseA) The difference in the forces attracting water molecules and those attracting hydrogen sulphide molecules is due to the difference in strength of the O-H and the S-H covalent bonds.B) The bonds in hydrogen sulphide are easily broken whereas those in water are not.C) The hydrogen sulphide molecules are closer to each other, leading to greater attraction between molecules.D) The forces between water molecules are stronger than those between hydrogen sulphide molecules.4. In hydrogen chloride, HCl, the bond between hydrogen and chloride is a/an(1) covalent (2) ionicbecauseA) Electrons are shared between atoms.B) Electrons are transferred.C) It contains different atoms.D) It contains Cl atom.7. When NaCl dissolves in water, there is still ionic bonds between sodium and chlorine atoms in solution(1) True (2) FalsebecauseA) NaCl exists as discrete pairs of Na+ and Cl-.B) Ionic bond is broken during the dissolving process.C) Positive charge on sodium ions must be neutralized by gaining of electronsfrom chloride ions in the solution.D) NaCl is still molecular in water.8. NaCl in water conducts electricity(1) True (2) FalsebecauseA) It contains ions that carry an electric current.B) It contains molecules that do not conduct a current.C) It contains covalent bonds between molecules.D) Covalent bonds are broken in solution.12. Element X (electronic configuration 2, 8, 18, 8, 2) and element Y (electronic configuration 2,7) react to form an ionic compound, XY2.(1) True (2) FalsebecauseA) An atom of X will share one pair of electrons with each atom of Y to form a covalent molecule, XY2.B) Covalently bonded atoms of X and Y form a network covalent compound.C) X will transfer two electrons to Y to form an ionic compound XY2.D) X will transfer one electron to Y to form an ionic compound XY.10. The boiling point of N2 is very low (-147 0C), on the other hand, at high temperatures, it does not decompose due to(1) intermolecular bonds (2) intramolecular bondsbecauseA) Intermolecular forces between N2 molecules are very strong.B) Nitrogen atoms can not achieve stable octet.C) Intramolecular forces are weaker than intermolecular forces.D) Triple bond is very strong compared to intermolecular (Van der Waals) forces.6. The bonds in H2O are(1) polar (2) nonpolarbecauseA) Shared electrons are attracted equally.B) Shared electrons concentrate around one atom.C) Nonbonding electrons affect the position of shared electrons.D) Valance electrons in each atom determine polarity.9. Solid Cu conducts electricity(1) True (2) FalsebecauseA) It contains metallic bond which provides electron moving.B) It contains covalent bond.C) It contains ionic bonds.D) It exists as a molecule.11. The compound formed between magnesium and oxygen can be used asa heat resistant material to line of furnaces(1) True (2) FalsebecauseA) The covalent bonds between magnesium and oxygen atoms are strong.B) The intermolecular forces between the magnesium oxide molecules areweak.C) There are strong ionic forces between magnesium and oxide ions in thelattice.D) The intramolecular forces within the magnesium oxide molecules arestrong.