3. Phosphorus VIOLATES the 'octet rule' in biological molecules by _____. forming less than eight covalent bonds forming more than eight covalent bonds having less than eight electrons in its valence shell after covalent bonding having more than eight electrons in its valence shell after covalent bonding NOT forming covalent bonds The octet rule says that atoms react chemically in order to obtain 8 electrons in their outer shell. However, some atoms like hydrogen and phosphorus do not follow this rule. Hydrogen fills its outer shell with only 2 electrons (by forming 1 covalent bond), and phosphorus fills its outer shell with 10 electrons (by forming 5 covalent bonds). This was also covered in lecture.
4. When an oxygen atom and a hydrogen atom form a covalent bond, _____ is produced. a nonpolar covalent bond a polar covalent bond a hydrogen bond a van der Waals interaction an unstable bond This is a straightforward question, yet about a quarter of the class missed it; most who did chose ‘hydrogen bond’. A hydrogen atom that is covalently bonded to oxygen COULD go on to form a hydrogen bond, but that doesn’t mean it will. Read the questions carefully so that you know what they are saying; then choose the most direct answer. 5. Which of the following types of chemical bonds and interactions are relatively WEAK in cells? hydrogen bonds ionic bonds covalent bonds hydogen bonds and ionic bonds hydogen bonds, ionic bonds, and covalent bonds Why are ‘ionic bonds’ not strong within cells ? This question is ‘right out of the lecture’.