Chemical Bonding notes

4.1 - Ionic Compounds

• Ion: An Atom with a charge.

• 2 types of Ions: Cations (positive), and Anion (Negative).

• Elements become Ions to have a complete outer shell (to become stable).

• Octet rule with a few exceptions. Ie hydrogen (H)

IONIC BONDING

• In an Ionic compound, atoms GAIN or LOSE electrons to be stable.

• Happens between a Metal (Cation) and a Nonmetal (Anion).

• One atom is more attracted to electrons than others and will steal/take its valence electrons.

• Electronegativity: the attraction between nucleus and valence electrons. 

• Structural Formula

Covalent

Ionic picture

IONIC BONDING PROPERTIES

• Forms a crystal lattice structure 

• High melting/boiling points

• Hard and rigid 

• Do NOT conduct electricity as solids

4.2 - Metallic Bonding

• Happens between 2 Metals

• Interaction between delocalized electrons and the metal nuclei.

• Delocalized: when valence electrons are freely moving ( not local to any one metal atom)

• Forms a lattice of positive ions in a “sea of electrons” -> Metal atoms donate their valence electrons to form a “sea”

• Electrons are freely moving

• Malleable and ductile

4.3 - Covalent Bonding

• Happens between 2 nonmetals (anions)

• Both nonmetal atoms will have high electron affinity (Electronegativity) which will cause the atoms to SHARE their electrons

IONIC BONDS

• Metal + Nonmetal

• Electrons transfer

• Higher melting/boiling points

• STRONGEST BOND

COVALENT BONDS

• Nonmetal + Nonmetal

• Electrons shared

• Low melting/boiling point

Types Of Covalent Bonds

• Single Covalent Bonds H - H

• Double Covalent Bonds O = O

• Triple Covalent Bonds N ≡ N

• A triple bond is stronger, cuz it has more electrons being shared

• Each bond represents 2 electrons being shared.

DIATOMIC ELEMENTS

• Diatomic elements are elements that exist in nature as 2 covalently bonded atoms

• Like cl - cl   br - br  fl - fl   o = o

• Hydrogen - H^2

• Nitrogen - N^2

• Oxygen - O^2

• Fluorine - F^2

• Chlorine - Cl^2

• Bromine - Br^2

• Iodine - I^2

VSEPR MODEL: Valence Shell Electron Pair Repulsion

• Shows the 3-D structure of covalent Bonds

• Linear - 2 atoms on the central atom

• Bent - 2 atoms on central atom + 2 lone pairs

• Trigonal Planar - 3 atoms on central atom

• Trigonal Pyramidal - 3 atoms on central atom + 1 lone pair

• Tetrahedral - 4 atoms on the central atom

• Lone Pair - pair of electrons not used in bond

You don't gotta know the angle I think

Polarity

• In polar covalent bond, electrons aren't shared equally

• One element is pulling harder due to electronegativity

• Nonpolar covalent bonds share electrons equally

• Polar covalent bonds do NOT share electrons equally

• Find the difference between polarity

• EN diff = 0 ------> nonpolar covalent bond

• EN diff = 0.1-1.7 --------> polar covalent bond

• EN diff = > 1.7 (more than 1.7) -----> Ionic bond

• Polar molecules have both partial positive and partial negative poles

• This depends on 

 - Structural formula/ shape of molecule

- Polar bonds

- Separation of charge into oppositely charged poles

• You can also use the flow chart (green = yes, red = no)

4.5 - Naming Binary Ionic Bonds

• Cation First, then Anion

• Add -Ide on the Anion

• NaCl

• Sodium Chlorine → Sodium Chloride

Writing Binary Ionic Formulas

• The scientific term for the charge is oxidation number

• Crisscross to write the bonds in a formula

When writing binary ionic compounds

• Net charge = 0

• Positive ion first

• Cross charges to get subscript hi miwin :3

POLYATOMIC IONS

• When naming: Cation + Polyatomic Ion

• Name both as is on the chart (NO IDE)

• Put parentheses when using more than one PA Ion

• Treat PA as one unit, do NOT change subscripts inside the parentheses

MULTIVALENT IONIC BONDS

• Aka funny metals, need Roman numerals to indicate the charge

• Name the funny metal (cation) as it appears

• Find charge for funny metal using REVERSE CRISS CROSS (use the subscripts to find charge)

• Use Roman numerals (ie II, III, IV) after the funny metal to show its charge

• Name anion using ide, if PA then write PA as is

NAMING COVALENT COMPOUNDS

• Needs a prefix (ie carbon dioxide, CO2)

1 - Mono

2 - Di

3 - Tri

4 - Tetra

5 - Penta 

6 - Hexa

7- Hepta

8 - Octa

9 - Nona

10 - Deca

• The first element will have a prefix unless it is only one, use a normal name, (no ide on first element)

• NEVER use mono on the first atom

• The second atom ALWAYS has a prefix

EXAMPLES

• S4O2 - Tetrasulfur Dioxide

• P205 - Diphosphorus PentoxidePentaoxide

• NH3 - Nitrogen Trihydride

NAMING ACIDS

• Starts with H (hydrogen) because it dissolves in water

• If binary (H and a nonmetal)

• Use the prefix hydro and change the end of nonmetal to -ic

• Ie HBR - Hydrobromic Acid

• H2S - Hydrosulfuric Acid

IF POLYATOMIC IS INVOLVED

• Don't use the prefix hydro

• If PA ends in ATE change to IC “I ATE something gross and said IC”

• Ie HNO3 (hydrogen + nitrate) - Nitric Acid

• If PA ends in ITE change to OUS “venomOUS snakes bITE”

• Ie HNO2 ( hydrogen + nitrite) - Nitrous acid