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
determine the electronic configuration of atoms and ions given the atomic or proton number and charge, using either of the following conventions: e.g. for Fe: \( 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2 \) (full electronic configuration) or \( [Ar] 3d^6 4s^2 \) (shortband electronic configuration)
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
