Concept explainers
To review:
The following bonded atoms and questions:
a. Whether the given bonded atoms have nonpolar or polar bonds?
b. Which of the ends contain δ− in polar molecules?
c. Whether the contribution of an atom pair is hydrophobic or hydrophilic in nature.
Given:
Table 1: Number of covalent bonds formed by elements of biological importance.
Element | Number of covalent bonds |
Hydrogen (H) | 1 |
Oxygen (O) | 2 |
Sulfur (S) | 2 |
Nitrogen (N) | 3 |
Carbon (C) | 4 |
Phosphorus (P) | 5 |
Table 2: Electronegativities of some biologically important elements.
Element | Electronegativity |
Oxygen (O) | 3.5 |
Chlorine (Cl) | 3.1 |
Nitrogen (N) | 3.0 |
Carbon (C) | 2.5 |
Phosphorus (P) | 2.1 |
Hydrogen (H) | 2.1 |
Sodium (Na) | 0.9 |
Potassium (K) | 0.8 |
Introduction:
The polarity of a particular compound depends upon the electronegativities of the atoms that are involved in its formation. If the electronegativity of the atoms is comparable then the compound formed is nonpolar. A large difference in the electronegativities of the atoms makes a compound polar.
The polar compounds are hydrophilic as they make bonds with water, usually called as hydrogen bonding. The nonpolar compounds are hydrophobic because they interact with each other rather than water.
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Life: The Science of Biology
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