How often Chemical bonding and Lewis structures is asked
4 of 4
papers asked it
avg 17 marks · last May 2018
Worth 1–7 marks when it appears as a written question, plus 3 multiple-choice items.
Where it was asked
The questions
Oct/Nov 2017, Q1.22 marks · multiple choice
The oxyanions ClO⁻ and ClO₄⁻ are respectively called:
Oct/Nov 2017, Q4.15 marks
Draw the most stable Lewis structure(s) for the thiocyanate ion, SCN⁻. Use formal charges and the electronegativity of the atoms involved to justify and support your final chosen structure.
Oct/Nov 2017, Q4.25 marks
A diagram is given showing part of a nucleotide structure: an adenine base attached via a glycosidic linkage to a deoxyribose sugar, which is in turn linked to a phosphate group bearing a sodium ion, with a zinc ion shown coordinating to a hydroxyl oxygen on the sugar, and a hydrogen atom shown interacting with the amine nitrogen of the adenine ring. Five bonds in this structure are labelled with the letters A, B, C, D and E: A is the bond between sodium (NaO) and the phosphate group; B is the bond between the two carbon atoms of the sugar ring; C is the bond between the sugar ring carbon and the nitrogen of the adenine base; D is the dashed interaction between the ring nitrogen (HN) and a hydrogen atom; and E is the dashed interaction between the zinc atom and the hydroxyl oxygen (HO) on the sugar. For each of the bonds labelled A to E, identify the type of chemical bond represented.
Oct/Nov 2017, Q4.34 marks
Apply VSEPR (Valence Shell Electron Pair Repulsion) theory to work out and explain the molecular geometry of the molecules XeF2 and BeF2.
Oct/Nov 2016, Q1.22 marks · multiple choice
State what the oxyanions IO2- and ClO4- are respectively called.
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