Lewis Dot Diagrams
What does the dot in the Lewis Dot Diagram represent?
The valence electron.
Describe Metallic Bonding
Two metals (usually the same) surrounded by a sea of electrons that are freely moving.
Two nonmetals sharing electrons is called
Covalent Bonding
Define Intermolecular Forces.
Forces of attraction between two molecules.
Define Polar.
A difference in electronegativity between two atoms.
H• + •H --> H:H
What is the range of the difference in electronegativity for polar covalent compounds?
The difference in electronegativity is between 1.7 and 0.4
What does the acronym BARF stand for?
What does it tell us about energy and bonding?
Break, Absorb, Release, Form.
Energy is absorbed when bonds are broken (Endothermic), and energy is released when bonds are formed (Exothermic).
List & Rank the three types of intermolecular forces from weakest to strongest.
London Dispersion Forces < Dipole-Dipole
< Hydrogen Bonding
Molecular Shape of H2O.
Bent.
Water is Bent.
Two part question
A) What is the ideal number of electrons an atom wants in its outer shell?
B) What is the rule called?
A) 8 valence electrons in its most outer shell.
B) The Octet Rule
Name three ways to recognize Ionic Bonds
☼ Metal + Nonmetal
☼ Metal transfers electron to the nonmetal
☼ A difference in electronegativity greater than 1.7
☼ Substance does not conduct electricity in the solid form, but does conduct electricity in the liquid or aqueous form.
Name the following substances correctly.
(Do not use common names)
CO2
CO
N2O3
H2O
Carbon Dioxide
Carbon Monoxide
Dinitrogen Trioxide
Dihydrogen Monoxide
In order to have hydrogen bonds, what three possible elements must Hydrogen (H) be covalently bonded to?
(F) Fluorine
or
(O) Oxygen
or
(N) Nitrogen
How do we know if something has nonpolar covalent bonds?
Difference of electronegativity between the two atoms is less than 0.4
How many electrons are shared in an N2 molecule?
6 Electrons are shared.
3 from the first nitrogen and 3 from the second nitrogen.
N≡N
Two part question
A) Name the following ionic compounds correctly.
CuCl2, CuCl, FeBr2, FeBr3
B) What do those "numerals" represent?
A) Copper (II) Chloride, Copper (I) Chloride, Iron (II) Bromide, Iron (III) Bromide.
B) The roman numerals represent oxidation states (charges) of the transition metals.
List three properties of metallic bonds
Malleable & Ductile
High Melting and Boiling Points
Conducts electricity in solid and liquid form
Conducts heat
Show a drawing of how water molecules interact with a Sodium Ion.
The oxygen (partial negative) will be attracted to the positive charge on the Calcium.
What does the term "like dissolves like" mean?
Polar substances will dissolve in polar substances.
(Ionic compounds will also dissolve in polar substances)
Nonpolar substances will dissolve in nonpolar substances.
Two part question
A) Draw the Lewis Dot Diagram for OCS
B) Is it a polar or nonpolar molecule? Why?
Both A & B must be correct in order to get points.
B) Polar, structure is not symmetrical.
O = C = S
In covalent bonds, a double bond contains ______ many electrons.
4
Write a formula and name the substance that contains both Ionic & Covalent bonds.
It must be balanced and correctly named.
Any metal + polyatomic ion will satisfy the answer.
Remember, polyatomic ions are covalently bonded (two or more nonmetals sharing electrons)
When it is joined with a metal, it forms an ionic bond
Some Examples:
Calcium Phosphate Ca3(PO4)2
Sodium Carbonate Na2CO3
Aluminum Sulfate Al2(SO4)3
Potassium Hydroxide KOH
Lithium Nitrate LiNO3
Explain how a nonpolar molecule can have polar covalent bonds.
Polar covalent bonds can exist in nonpolar molecules if the molecule is symmetrical, then the electron distribution is evenly spread out across the whole molecule.
Two part question:
A) Draw & name the molecular structure of ammonia (NH3)
B) How many nonbonding pairs and bonding pairs are present on the central atom N?
A) Ammonia is Trigonal Pyramidal (Tetrahedral)
B) There is 1 nonbonding pair (Lone Pair of Electrons) and 3 bonding pairs (Shared bonds with Hydrogen)