Ionic and Covalent Bonding: Key Concepts for Chemistry

Ionic Bond

Chemical Bond Formed by transfer of electrons

Ionic Compound

positive and negative ions held together by ionic bonds

Cation

Positively charged

Anion

Negatively charged

Valence electron

Outermost energy level

Formula unit

simplest whole number ratio subscripts in a chemical formula

Crystal-lattice

solid structure of ionic bonds - alternating/repeating charge patter

Monatomic ion

one single element ion --> Na+

Polyatomic ion

two or more element ions --> Sulfate (PO4)-3

Electron sea model

metal atoms release some of their electrons which move freely throughout the metal like a "sea"

Delocalized electron

electrons that are not tied to one specific atom

Alloy

mixture of two or more elements, where one of them is a metal

Electronegativity

ability to attract electrons

Ionization energy

energy it takes to remove an electron

Atoms form ions, and ionic bonds to gain stability by achieving a full valance shell. True/False

True

Octet Rule

Atom with 8 electrons in valence shell

Ionic bonds form between what

metal and nonmetal

Metals form what when they lose electrons

Cations

Non metals form what when they gain electrons

Anions

Properties of ionic compounds

High melting/boiling point, hard brittle, crystal lattice, strong electrostatic attraction, solid/liquid, conduct electrcity when dissolves,soluble in water

Molecule

group of two or more atoms covalently bonded together

Covalent bond

chemical bond where atoms share electrons to become stable

Lewis Structure

diagram that shows how the valence electrons are arranged in a molecule (sharing of electrons)

Expanded Octet

more than 8 electrons in a valence shell

suboctet

less than 8 electrons in a valence shell

Polar Covalent Bond

electrons are shared equally -- electronegativity difference of 0.5 - 1.7

Nonpolar Covalent bond

electrons are shared unequally -- electronegativity difference of 0.0-0.4

Diatomic Molecule

One element atom bonded to itself

Nonpolar covalent bond is when

Electrons are shared equally

A polar covalent bond is when

Electrons are shared unequally

Properties of metals

Conduct heat/electricity, malleable, ductile, luster when polished, high melting point, form alloys, solids

Properties of covalent compounds

Low melting point, do not conduct, all forms, insoluble, share electrons

Single bond

Longest, weakest

double bond

Medium length, medium strength

Triple bond

shortest and strongest