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Pages and Files
**Pictures of Chem Class ^_^
*General Suggestions for Student Pages
*Organic seminar sign-up
*Periodic Table Assignment
*Topic (I) --> Sign-up
*Topic (II) --> Review
*Topic (III) --> Stage of Page
*Unit 8 Topics
Aldehydes and Ketones
Alkenes and Alkynes
Amines and Amides
An overview of molarity problem
Atomic Mass and Avogadro's Hypothesis
atomic number and mass
Balancing Chemical Reaction Equations
Basic Science definitions.
Calculations involving the Mole and the Mass of a Substance and the Volume of a gas
Calculations involving the Mole and the Volume of a gas and the Number of Particles
Certain & Uncertain Digits, Defined Numbers and Accuracy & Precision
Chemical Equations and the Conservation Laws
Chemical families -- by Judy Bai
Classification of matter
Concentration of ions in Solution
Constructing the name of an Ionic Compound
Derived Quantities and Density
Early atomic models
Electrostatic forces, electron shells, Valence electrons and valence of an atom
Energy Changes in Chemical Reactions
Ethers and Carboxylic Acids
History of the period table
How to Classify Atoms and Ions
How to Read a Scale
INTERMOLECULAR FORCES AND BONDING
Introduction to functional groups and Alcohols---Elizabeth
Introduction to organic chemistry and hydrocarbon
Ionization energy, Electron Affinity, Atomic Radius
Isotopes and their mixtures
Lab safety 2
Later atomic models
Lewis Dot Diagrams of Neutral Atoms, Monatomic Ions,and Ionic Compounds
LIine spectra, electron shells and energy level diagrams
Mixing Two Solutions and Making Dilute Solutions
Molar Concentrations and Making up Solutions
Multiple conversions between moles,mass, volume and number of particles
Multiplying & Dividing and Adding and Subtracting with Sig Figs
Naming Hydrates and Naming Compounds Using the Prefix System
Naming Monatomic and Polyatomic Ions
Percent Yield and Purity
Phase Changes--by AnnYU
Phases, the Magic 7 and Chemical Word Equation
polar and nonpolar solvents
SI Units and Metric Unit conversions
Significant Figures & Zeros
Solutions and Solubility Introduction
Solving Problems that Involve Multiple Operations and Sig Figs
Stoichiometery calculation involvingMoles, Mass, Gas volume and Molecules
Stoichiometry Calculations Involving Molar Concentration
Stoichiometry of Excess Quantities
The Conductivity of Aqueous solutions
The Major divisions of the periodic table & Metals Non-metals and semi conductors
The Meaning of Stoichiometry and the Coefficients in a Reaction Equation
The Mole Concept and Finding Molar Mass
The nature of covalenting bonding & Predicting the formula of covalent bonds
The nature of solutions of ions
The Physical separation of substances
THE PHYSICCAL PROPERTIES OF MATTER
The role of Kinetic Energy in Phase Changes
TO DRAW A Lewis dot diagrams of covalent compounds
Types of Chemical Reactions - Combustion (Pt.2) &Summary
Types of Chemical Reactions - First 4 Types
Unbranched Alkanes and their Geometry
When to use each separation method
Writing electron configurations of atoms in full and core notation
Writing electron configurations of ions, and the copper and chromium exceptions
TO DRAW A Lewis dot diagrams of covalent compounds
Lewis dot diagram is a useful tool for us to study chemistry. Some times it's difficult for student do draw since they feel confused. So first of all, let's see what is a Lewis dot diagram!
, also called
Lewis dot diagrams
, are diagrams that
show the bonding between atoms of a molecule, and the lone pairs of electrons
that may exist in the molecule...The Lewis structure was named after Gilbert N. Lewis, who introduced it in his 191 article
The Atom and the Molecule
*Usually, in a Lewis dot diagram short dash between two elements means a bond. If there's only two single dots, it means a lone pair exits.
*Except hydrogen and helium, other elements have 8 electrons in the outer shell.
NOW, LET'S BEGIN TO PLAY!!
1). Use the table below to count how many valence electrons are being hold in the covalent compound.
Number of Valence Electrons
(alkali earth metals)
Group VIII except Helium
(electron dot diagram)
2). Look at the givin structure and time the # of bond by 2 to get the electrons that have been used.
3). Use the total number of valence electrons minus the result you get on the second step to figure out how many electrons can still be used.
: NF*N has1 valence electrons of 5 and F has the valence electrons of 7. For total, therea are 26 of them.
*Accroding to the give structure, H-F has ONE bond which means there are 2 electrons that have been used.
4). Put those electrons around the atoms and try to let every one of them have the full outershell with 8 electrons.
*Bonds(represents 2 electrons) are counted in both atoms it connects.
*When there is lack of electrons you can create bonds to make the elements full.
5). When every element (except H and He) get their valence electrons full, you're succeed!
EX: In oxygen gas, each oxygen atom holds 6 valence electrons. When you draw the Lewis Dot Daifram as they share 1 bond, each oxygen atom has 7 valence electrons. Now, we still need one electron on each side. So what can we do? Obvious to see, in the diagram we have 2 unpaired electrons on each side. The interesting thing is, when we join these two single electrons together, each oxygen atoms gets one extra electron since they share electron with each other. Redraw the structure with two bonds between the atoms and 8 electrons left around, what do you see? Two oxygen both reach the balance state.
Congratulations!!--now you have hold "drawing the Lewis Dots Diagram of covalent compound" in hand!!
In addition, if you have further questions please ask me, or have a look on these websites
CREATED BY MELODY LI BLOCK A
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