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Ionic bond. Pg. 53. Ions. An ion is an element that has gained or lost electrons Oxidation numbers are used to show the charge of an ion. A positive ion is called a cation A negative ion is called an anion. Writing ions . Write the element symbol first
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Ionic bond Pg. 53
Ions • An ion is an element that has gained or lost electrons • Oxidation numbers are used to show the charge of an ion. • A positive ion is called a cation • A negative ion is called an anion
Writing ions • Write the element symbol first • As a superscript, write the oxidation number • Ex. Ba2+ or Ba+2
Ionic Bonds • Force that holds oppositely charged ions together is called an ionic bond • Between a metal and a nonmetal • Electrons are lost or gained • High melting and boiling points • Can dissolve in water to produce electrolytes (produces an electric current) • Example: NaCl
Writing Ionic compound formulas • Lowest ratio called a formula unit • First write the ions with their oxidation numbers • The charges on each elements switch and become the subscripts on the other element • Take just the numbers, NOT THE CHARGES • Simplify • Examples: • Na and Cl • Mg and F • K and P • Be and O
Lewis Dot diagrams • Na and Cl • Mg and F • K and P • Be and O
Naming Ionic compounds • The cation is written as normal • The anion drops the last part of the element and add –ide • Example: Sodium + Chlorine = Sodium Chloride
Polyatomic ions • Ions made up of more than one element • Charge applies to the entire ion • Written in parenthesis in ionic formulas • Ex. Mg(OH)2
Ionic formulas with transition metals • Transition metals can have multiple oxidation numbers • When writing the name, the charge of the transition metal must go in parenthesis using Roman numerals • Ex. Iron (III) oxide • Cu3P2 • MnO