Older MCQs might not have the typical A, B, C,
D
choices. They
have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such
combinations to the answer.
A
1, 2 and 3 are correct
B
1 and 2 only are correct
C
2 and 3 only are correct
D
1 only is correct
define covalent bonding as electrostatic attraction between the nuclei of two atoms and a shared pair of electrons (a) describe covalent bonding in molecules including: - hydrogen, H\(_2\) - oxygen, O\(_2\) - nitrogen, N\(_2\) - chlorine, Cl\(_2\) - hydrogen chloride, HCl - carbon dioxide, CO\(_2\) - ammonia, NH\(_3\) - methane, CH\(_4\) - ethane, C\(_2\)H\(_6\) - ethene, C\(_2\)H\(_4\) (b) understand that elements in period 3 can expand their octet including in the compounds sulfur dioxide, SO\(_2\), phosphorus pentachloride, PCl\(_5\), and sulfur hexafluoride, SF\(_6\) (c) describe coordinate (dative covalent) bonding, including in the reaction between ammonia and hydrogen chloride gases to form the ammonium ion, NH\(_4^+\), and in the Al\(_2\)Cl\(_6\) molecule
(a) describe van der Waals’ forces as the intermolecular forces between molecular entities other than those due to bond formation, and use the term van der Waals’ forces as a generic term to describe all intermolecular forces (b) describe the types of van der Waals’ forces: • instantaneous dipole–induced dipole (id-id) forces, also called London dispersion forces • permanent dipole–permanent dipole (pd-pd) forces, including hydrogen bonding (c) describe hydrogen bonding and understand that hydrogen bonding is a special case of permanent dipole–permanent dipole forces between molecules where hydrogen is bonded to a highly electronegative atom
