Scope, Sequence, and Coordination
A Framework for High School Science Education
Based on the National Science Education Standards
The Periodic Table, Electrons and Chemical Bonds
Chemical Formulas and Chemical Bonds
Bonds between atoms are created when electrons are paired up by being transferred or shared. A substance composed of a single kind of atom is called an element. The atoms may be bonded together into molecules or crystalline solids. A compound is formed when two or more kinds of atoms bind together chemically.
Classes of compounds formed from the transfer or sharing of outer electrons can be distinguished on the basis of solubility and electrical conductivity.
The position of elements in the periodic table and information about related trends in atomic properties can be used to predict the formulas and properties of compounds. Formulas of compounds also can be deduced from quantitative information such as percent composition and molar mass.
Lewis dot diagrams can be written to show how outermost electrons in the constituent atoms are distributed.
Solubility, electrical conductivity, atomic symbols
Electron transfer, electron sharing, ionic bonds, covalent bonds, Lewis dot diagram, valence electrons, cations, anions
Molecular formula, empirical formula, percent composition
Bond energy, electronegativity, bond strength
The periodic law
Lewis electron-pair bond model, the chemical bond theory