Pupil sheet · Covalent molecules
Covalent molecules — final check
Name ______________________ Date ____________
Work alone, with the lesson closed. Answer every question; there are no hints.
1. describe / state / deduce
(a) Carbon is 2,4 and chlorine is 2,8,7. Describe how covalent bonds form in tetrachloromethane, CCl4, and describe its dot-and-cross diagram, outer shells only, with dots for carbon and crosses for chlorine. State the noble gas configuration each atom reaches. (b) Supplement: in methanal, CH2O, the carbon atom (2,4) is bonded to two hydrogen atoms and to the oxygen atom (2,6). Deduce the type of bond between carbon and oxygen, and the number of lone pairs on the oxygen atom and on the carbon atom.
(a) Tetrachloromethane
(b) Supplement: methanal
2. describe / deduce / explain
(a) Solid carbon dioxide (dry ice) turns to a gas at −78 °C and does not conduct electricity. Describe, in terms of structure and bonding, why. (b) Supplement: sulfur dioxide, SO2, is also a simple molecular substance; it boils at −10 °C. Deduce whether the intermolecular forces are stronger in carbon dioxide or in sulfur dioxide, and explain your answer.
(a) Low temperature and no conductivity
(b) Supplement: carbon dioxide or sulfur dioxide