High School Biology : Understanding Properties of Carbon
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Example Questions
Example Question #1 : Understanding Properties Of Carbon
All organic compounds contain which of the following elements?
Hydrogen
Sulfur
Carbon
Oxygen
Nitrogen
Carbon
Organic compounds are defined as solids, liquids, or gases whose molecular structure includes carbon. Inorganic compounds, in contrast, do not contain carbon. Organic compounds might contain other elements, like hydrogen and oxygen, but not all compounds need these other elements to be considered organic.
Example Question #1 : Understanding Properties Of Carbon
What are the four most abundant elements found in living organisms?
Carbon, hydrogen, oxygen, sulfur
Hydrogen, carbon, oxygen, nitrogen
Hydrogen, nitrogen, oxygen, iron
Hydrogen, carbon, sulfur, nitrogen
Carbon, phosphorous, hydrogen, oxygen
Hydrogen, carbon, oxygen, nitrogen
Living organisms are primarily made up of organic molecules, which contain carbon. The six most prevalent elements in living organisms are carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur, in that order.
Carbon and hydrogen are found in the basic monomer structure of all biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids). Nitrogen is found in amino acids, which form proteins, and the nitrogenous bases in nucleic acids (DNA and RNA). Oxygen is found in all biological macromolecules. Phosphorous is found in nucleic acids and lipids, such as phospholipids in the cell membrane. Sulfur is found in cysteine, a specific amino acid.
Example Question #2 : Understanding Properties Of Carbon
Why does carbon tend to form four molecular bonds?
It has four valence electrons
It must balance its partial negative charge
It accepts four electrons to become more stable
It donates four electrons to become more stable
It is highly electronegative
It has four valence electrons
Since carbon is in group IV of the periodic table, we know that it has four valence electrons. Most elements (with the exceptions of hydrogen and helium) are most stable when they have filled their valence shell with eight electrons. For carbon to fill its valence shell, it needs to make four covalent bonds. Remember that carbon is not very electronegative and only very rarely (if ever) forms ionic bonds. This means that carbon will not donate, nor accept electrons; rather it will share them with other atoms to form molecules.
Example Question #18 : Attributes Of Life
One carbon atom has the ability to bind with __________ other atoms.
Carbon has four electrons in its valence shell which means it needs four more to have a stable octet. This means that the maximum number of bonds it can form is four when each bond only contributes one electron to the relationship.
Example Question #21 : Attributes Of Life
How many valence electrons does a carbon atom have?
6
4
3
8
2
4
One of the reasons carbon is so ubiquitous in biological structures is the fact that it has four valence electrons, meaning it likes to form four bonds to complete an octet in its outer shell. Being able to form four bonds means that it can bind to multiple other atoms covalently and with high stability.
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