This particular resource used the following sources:. Skip to main content. Liquids and Solids. Search for:. Hydrogen Bonding. Learning Objective Describe the properties of hydrogen bonding. Key Points Hydrogen bonds are strong intermolecular forces created when a hydrogen atom bonded to an electronegative atom approaches a nearby electronegative atom. Greater electronegativity of the hydrogen bond acceptor will lead to an increase in hydrogen-bond strength.
The hydrogen bond is one of the strongest intermolecular attractions, but weaker than a covalent or an ionic bond.
Hydrogen bonds are responsible for holding together DNA, proteins, and other macromolecules. Individual H 2 O molecules are V-shaped, consisting of two hydrogen atoms depicted in white attached to the sides of a single oxygen atom depicted in red. Neighboring H 2 O molecules interact transiently by way of hydrogen bonds depicted as blue and white ovals. Strong linkages—called covalent bonds—hold together the hydrogen white and oxygen red atoms of individual H 2 O molecules.
Negative ions are formed by gaining electrons and are called anions wherein there are more electrons than protons in a molecule. This movement of electrons from one element to another is referred to as electron transfer. As illustrated, sodium Na only has one electron in its outer electron shell.
It takes less energy for sodium to donate that one electron than it does to accept seven more electrons to fill the outer shell. When sodium loses an electron, it will have 11 protons, 11 neutrons, and only 10 electrons. It is now referred to as a sodium ion. Chlorine Cl in its lowest energy state called the ground state has seven electrons in its outer shell.
Again, it is more energy efficient for chlorine to gain one electron than to lose seven. Therefore, it tends to gain an electron to create an ion with 17 protons, 17 neutrons, and 18 electrons. This gives it a net charge of -1 since there are now more electrons than protons. It is now referred to as a chloride ion. In this example, sodium will donate its one electron to empty its shell, and chlorine will accept that electron to fill its shell. Both ions now satisfy the octet rule and have complete outer shells.
These transactions can normally only take place simultaneously; in order for a sodium atom to lose an electron, it must be in the presence of a suitable recipient like a chlorine atom. Electron Transfer Between Na and Cl : In the formation of an ionic compound, metals lose electrons and nonmetals gain electrons to achieve an octet. In this example, sodium loses one electron to empty its shell and chlorine accepts that electron to fill its shell.
Ionic bonds are formed between ions with opposite charges. For instance, positively charged sodium ions and negatively charged chloride ions bond together to form sodium chloride, or table salt, a crystalline molecule with zero net charge.
The attractive force holding the two atoms together is called the electromagnetic force and is responsible for the attraction between oppositely charged ions. Certain salts are referred to in physiology as electrolytes including sodium, potassium, and calcium.
Electrolytes are ions necessary for nerve impulse conduction, muscle contractions, and water balance. Many sports drinks and dietary supplements provide these ions to replace those lost from the body via sweating during exercise. Carbon is the most important element to living things because it can form many different kinds of bonds and form essential compounds.
Carbon is the fourth most abundant element in the universe and is the building block of life on earth. On earth, carbon circulates through the land, ocean, and atmosphere, creating what is known as the Carbon Cycle. This global carbon cycle can be divided further into two separate cycles: the geological carbon cycles takes place over millions of years, whereas the biological or physical carbon cycle takes place from days to thousands of years.
In a nonliving environment, carbon can exist as carbon dioxide CO 2 , carbonate rocks, coal, petroleum, natural gas, and dead organic matter. Plants and algae convert carbon dioxide to organic matter through the process of photosynthesis, the energy of light. Carbon is present in all life : All living things contain carbon in some form, and carbon is the primary component of macromolecules, including proteins, lipids, nucleic acids, and carbohydrates.
In its metabolism of food and respiration, an animal consumes glucose C 6 H 12 O 6 , which combines with oxygen O 2 to produce carbon dioxide CO 2 , water H 2 O , and energy, which is given off as heat.
The animal has no need for the carbon dioxide and releases it into the atmosphere. A plant, on the other hand, uses the opposite reaction of an animal through photosynthesis. It intakes carbon dioxide, water, and energy from sunlight to make its own glucose and oxygen gas.
The glucose is used for chemical energy, which the plant metabolizes in a similar way to an animal. The plant then emits the remaining oxygen into the environment. Cells are made of many complex molecules called macromolecules, which include proteins, nucleic acids RNA and DNA , carbohydrates, and lipids. The macromolecules are a subset of organic molecules any carbon-containing liquid, solid, or gas that are especially important for life. The fundamental component for all of these macromolecules is carbon.
Individual carbon atoms have an incomplete outermost electron shell.
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