Pearson Prentice Hall Physical Science: Concepts in Action Chapter 6 Chemical Bonds mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt

6.1 Ionic Bonding Objectives: mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt 6.1 Ionic Bonding Objectives: 1. Explain when an atom is unlikely to react 2. Indicate one way in which elements can achieve a stable electron configuration 3. Express how the structure of an ionic compound affects its properties This Photo by Unknown Author is licensed under CC BY-NC-ND This Photo by Unknown Author is licensed under CC BY-SA

When Atoms are Unlikely to React mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt When Atoms are Unlikely to React When the highest occupied energy level (the outer shell) is filled with electrons (valence electrons), the atom is stable and unlikely to react Like your Nobel Gasses The valence electrons can be represented by a special drawing called an electron dot diagram Remember the 2-8-8 rule. Two electrons in the first shell Eight in the second Eight in the third This Photo by Unknown Author is licensed under CC BY-SA

Achieving Stable Electron Configurations mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt Achieving Stable Electron Configurations Atoms can become stable by filling their outer shells with electrons Some elements achieve stable electron configurations by transferring electrons between atoms The gain or loss of electrons between the atoms then produces full shells & stability

mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt TYPES OF IONS The gain or loss of electrons also produces an atom with a net positive charge (lost one or more electrons) or a net negative charge (gained one or more electrons) Definition: an ion is an atom with a net positive or net negative charge Definition: an anion is an ion with a net negative charge Definition: a cation is an ion with a net positive charge

Definition: a chemical bond is the force that holds atoms or ions together as a unit Definition: an ionic bond is the force that holds cations and anions together Definition: an ionic bond is the bond that forms when electrons are transferred from one atom to another mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt This Photo by Unknown Author is licensed under CC BY-SA

Structure and Properties mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt Many ionic compounds are solid at room temperature IONIC COMPOUNDS GENERALLY CONSIST OF A METAL + A NONMETAL Their molecular structure has an orderly repeating three dimensional structure called a lattice Definition: solids whose particles are arrange in a lattice are called crystals The properties of an ionic compound can be explained by the strong attractions among the ions in a crystal lattice

mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt 6.2 Covalent Bonding

How Atoms Are Held Together in a Covalent Bond mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt Definition: a covalent bond is a chemical bond in which two atoms share a pair of valence electrons Definition: a molecule is a neutral group of atoms that are joined together by one or more covalent bonds The attractions between the shared electrons & the protons in each nucleus hold the atoms together in a covalent bond It is possible for more than one pair of electrons to be shared producing a double or triple covalent bond

Polar Attractions mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt Attractions between polar molecules are stronger than attractions between nonpolar molecules “Like attracts like”: polar molecules are attracted to polar molecules while nonpolar molecules are attracted to nonpolar molecules Q: What does the subscript 2 in the formula for the hydrogen molecule (H2) mean?

Unequal Sharing of Electrons mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt IN GENRAL, COVALENT MOLECULES CONSIST OF TWO NONMETALS Definition: a polar covalent bond is a covalent bond in which the electrons are not shared equally When atoms form a polar covalent bond, the atom with the greater attraction for electrons has a partial negative charge The other atom has a partial positive charge Water is an example WATER IS “MICKEY MOUSE” AND HE’S COLD. WATER MOLECULE IS POLAR This Photo by Unknown Author is licensed under CC BY-NC-ND

Factors that Determine Polarity mcqscience.weebly.com/uploads/1/3/3/8/13381369/pearson_ps_ch_6_edline.ppt Factors that Determine Polarity The type of atoms in a molecule and its geometric shape are factors that determine whether a molecule is polar or nonpolar Example: CO2 is linear, while the water molecule is bent