SCI 2201: Concepts in Science
Discussion Topic: Atoms in Combination: Chemical Bonding
Trefil and Hazen The Sciences Chapter 10
This discussion should help you to:
Atoms in Combination: The Chemical Bond (chap. 10 Trefil & Hazen)
1. relate chemical properties of the elements to electron arrangements in the atoms.
2. define a chemical bond and discuss the differences between the transfer of electrons
between atoms (ionic bonding) and the sharing of electrons between atoms (covalent
bonding).
3. determine chemical formulas for ionic and covalent compounds from representative
elements.
4. interpret periodic trends resulting from “shield effect” and “proton pull.”
5. apply the periodic trends of ionization energy and electron affinity to chemical properties
of various elements.
6. describe how metallic bonds differ from ordinary ionic bonds.
7. discuss the differences between the transfer of electrons between atoms and the sharing
of electrons between atoms.
8. define “chemical reaction” and interpret chemical equations.
9. relate the law of conservation of mass to balanced chemical reactions.
Relates to GPS
SKP1: Properties of materials; S2P1: Changes in Materials; S5P2: Physical/Chemical Changes
Science Literacy Benchmarks
(AAAS, 1993, 10.F: Understanding Fire; 4.D: Structure of Matter).
By the end of the 12th grade, students should know that
 Lavoisier's system for naming substances and describing their reactions
contributed to the rapid growth of chemistry by enabling scientists everywhere to
share their findings about chemical reactions with one another without ambiguity.
 John Dalton's modernization of the ancient Greek ideas of element, atom,
compound, and molecule strengthened the new chemistry by providing a physical
explanation for reactions that could be expressed in quantitative terms.
 There are groups of elements that have similar properties, including highly
reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine,
fluorine, and oxygen), and some almost completely nonreactive gases (such as
helium and neon). An especially important kind of reaction between substances
involves combination of oxygen with something else—as in burning or rusting.
Some elements don't fit into any of the categories; among them are carbon and
hydrogen, essential elements of living matter.
 The idea of atoms explains the conservation of matter: If the number of atoms
stays the same no matter how they are rearranged, then their total mass stays the
same.
 Atoms are made of a positive nucleus surrounded by negative electrons. An
atom's electron configuration, particularly the outermost electrons, determines
how the atom can interact with other atoms. Atoms form bonds to other atoms by
transferring or sharing electrons.