Hi Steve, Thank you for your help. I'm on my Easter break so I really want to get the chemistry right before next term starts. I have some questions, could you please check if I've done them correctly? Its in the word document and I've put my answers in italic.
PS, could you please explain Q5, I'm having some trouble because there is a double bond...
Q1) The hybridisation of the central nitrogen atom in N2O is: b)
Correct (sp hybridized).
Q2) In which case is the bond polarity INCORRECT? a)
Correct. In chlorine iodide, Cl-I, Cl is more electronegative and will therefore have the δ�?/SUP> charge.
Q3) Which of the following bonds is LEAST polar? d)
The least polar bond occurs in Br2, in which the difference in electronegativities is zero. This is a totally nonpolar bond.
Q4) Which of the following is a correct Lewis structure? a)
Structure a) has only 16 valence electrons, so it can't be right (the NO2 molecule has 17 valence electrons). So..... pick the structure that has 17 valence electrons and does not violate the octet rule on any atom (except the atom with the lone electron; it will have 7 electrons around it).
Q5) The bond angles around the carbon atom in the formaldehyde molecule (H2C=O) are approximately: d)
What is the hybridization of the central carbon atom? From that you can get the geometry and bond angles. Or, how many atoms and/or lone pairs are attached to the central carbon? Which geometry gives the maximum bond angles around the central carbon?
It is actually a distorted trigonal plane due to the greater repulsion of the oxygen. The O–C–H bond angles are about 121.3° and the H–C–H bond angle is about 117.5°. So it is a distorted trigonal plane, but we call it trigonal planar anyway.
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