Unit 4 Chemistry

The Octet Rule

The principle stating that atoms tend to gain, lose, or share electrons until they possess $8$ valence electrons, achieving a stable, low-energy noble gas configuration ($ns^2np^6$).

Properties of Ionic Compounds

crystals, Hard and brittle, High melting and Boiling points, Good Conductors

Ionic Bonding

The transfer of valence electrons from a metal (forming a cation) to a nonmetal (forming an anion).

Covalent Bonding

The sharing of valence electrons between two or more nonmetal atoms

Electron Dot Structures (Lewis Structures)

A structural representation where valence electrons are depicted as dots, shared electron pairs as lines (bonds), unshared pairs as lone dots

Formula Unit

The lowest whole-number ratio of ions, the basic structural unit of an ionic compound

Properties of moleculecular compounds

The basic unit of a covalent compound, nonmetals, low melting and boiling points

Empirical Formula

A chemical formula expressing the simplest whole-number ratio

Structural Formula

shows were each atom in compound are located and angles they create

Single Bond

A covalent bond formed by sharing 1 pair of electrons

Double Bond

A covalent bond formed by sharing 2 pairs of electrons

Triple Bond

A covalent bond formed by sharing 3 pairs of electrons

VSEPR Theory

Valence Shell Electron Pair Repulsion electron pairs surrounding a central atom repel each other and arrange as far apart as possible

Dash-Wedge Notation

l drawing showing where straight lines represent bonds in the plane, solid wedges point forward , and dashed wedges point backward

Linear Geometry

A molecular shape with 2 bonded and 0 lone pairs 180 degrees

Trigonal Planar Geometry

A molecular shape with bonded atoms and 0 lone pairs 120 degrees

Bent Geometry

A molecular shape with 2 bonded atoms and 1 lone pair 117.5 degrees

Tetrahedral Geometry

A molecular shape with 4 bonded atoms and 0 lone pairs 109.5 degrees

Trigonal Pyramidal Geometry

A molecular shape with 3 bonded atoms and 1 lone pair 107 degrees

Chemical Formula to Name for ionic compounds 

Write name of the metals, then for single take root and add ide, for Polyatomic add item or ate

Trigonal Bipyramidal Geometry

A molecular shape with 5 bonded atoms and 0 lone pairs 90 and 120 degrees

Nonpolar bond

A bond where electrons are shared equally between two atoms

Polar bond

A bond in which electrons are shared unequally due to an electronegativity difference.

Roman numeral

used to indicate charge of transition metal in parenthesis

Monatomic Ions

Single atoms that have gained or lost electrons to obtain a positive or negative charge

Polyatomic Ions

2 or more covalently bonded atoms

Formula for writing ionic compounds

balance the positive and negative charges so the overall net charge is zero

Prefixes

mono-1, di-2, tri-3, tetra-4, penta-5, hexa-6, hepta-7, octa-8, nona-9, deca-10

Naming Acids

My ride has hydrolics

I ate something icky

Sprite is delicious

Naming covalent bonds

Keep the first element the same, then for the second add its ending like ,ide, ite, ate. After that add a prefix to correspond with number of that compound.

Writing formulas for covalent bond

Look at ending of last word and write down compound elements, them use prefix to put down the number that corresponds. Then write the first one and only a number if there is a prefix in front of the first compound