S h h o h h water hydrogen sulfide nitrogen and

This preview shows page 13 - 16 out of 55 pages.

S H H O H H Water Hydrogen sulfide Nitrogen and phosphorus, which are in group 5A, have atoms with five valence electrons: P N They form three covalent bonds to pair their three unpaired electrons and achieve an octet of electrons around each atom. Ammonia, NH 3 , and phosphorus trichloride, PCl 3 , molecules are examples. N H H H Ammonia Phosphorus trichloride P Cl Cl Cl PCl 3 is used to make pesticides and gasoline additives. O BJECTIVE 11 O BJECTIVE 11 O BJECTIVE 11
Image of page 13

Subscribe to view the full document.

Carbon, in group 4A, has four unpaired electrons in its electron‑dot symbol. C Predictably, carbon atoms are capable of forming four covalent bonds (with no lone pairs). Examples include methane, CH 4 , the primary component of natural gas, and ethane, C 2 H 6 , and propane, C 3 H 8 , which are also found in natural gas, but in smaller quantities. H H H H C H H H H C H H C H H H H C H H C H H C Methane Ethane Propane Methane, ethane, and propane are hydrocarbons , compounds that contain only carbon and hydrogen. Fossil fuels that we burn to heat our homes, cook our food, and power our cars, are primarily hydrocarbons. For example, natural gas is a mixture of hydrocarbons with from one to four carbons, and gasoline contains hydrocarbon molecules with from six to twelve carbons. Like the hydrocarbons described above, many of the important compounds in nature contain a backbone of carbon‑carbon bonds. These compounds are called organic compounds, and the study of carbon‑ based compounds is called organic chemistry . Figure 3.8 Household Hydrocarbon Liquid petroleum gas is a mixture of the hydrocarbons propane and butane. O BJECTIVE 11 Table 3.1 shows electron‑dot symbols for the nonmetallic atoms and lists their most common bonding patterns. Note that the sum of the numbers of bonds and lone pairs is always four for the elements in this table. Propane, C 3 H 8 Butane, C 4 H 10 82 Chapter 3 Chemical Compounds Web Molecules
Image of page 14
3.3 Molecular Compounds 83 Table 3.1 Electron-Dot Symbols and Usual Numbers of Bonds and Lone Pairs for Nonmetallic Elements Group 4A Group 5A Group 6A Group 7A 4 valence electrons X 5 valence electrons X 6 valence electrons X 7 valence electrons X 4 bonds No lone pairs 3 bonds 1 lone pair 2 bonds 2 lone pairs 1 bond 3 lone pairs carbon‑C C nitrogen‑N N oxygen‑O O fluorine‑F F phosphorus‑P P sulfur‑S S chlorine‑Cl Cl selenium‑Se Se bromine‑Br Br iodine‑I I Atoms can form double bonds , in which four electrons are shared between atoms. Double bonds are represented by double lines in a Lewis structure. For example, in a carbon dioxide molecule, CO 2 , each oxygen atom has two bonds to the central carbon atom. C O O Note that each atom in CO 2 still has its most common bonding pattern. The carbon atom has four bonds and no lone pairs, and the oxygen atoms have two bonds and two lone pairs.
Image of page 15

Subscribe to view the full document.

Image of page 16
You've reached the end of this preview.
  • Fall '06
  • Mark
  • Atom, atoms, Chemical bond

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern