Bonding.

Slides:



Advertisements
Similar presentations
Chemical Bonding Objectives: 1.describe the nature of a chemical bond and its relationship to valence electrons 2.compare ionic and covalent bonding 3.use.
Advertisements

CHEMICAL BONDING IONIC BONDS COVALENT BONDS HYDROGEN BONDS
Chemical BONDING.
Chemical Bonds.
CHAPTER 7 & 8 BONDING. Valence Electrons – the outer most electrons that are involved in bonding Ex. Ion – an atom or group of atoms that has a positive.
Chemical BONDING. Chemical Bond A bond results from the attraction of nuclei for electrons –All atoms trying to achieve a stable octet IN OTHER WORDS.
Created by C. Ippolito Dec 2006 Chemical Bonding Objectives: 1.describe the nature of a chemical bond and its relationship to valence electrons 2.compare.
Forces that hold atoms together.  There are several major types of bonds. Ionic, covalent and metallic bonds are the three most common types of bonds.
 Bonds can be classified as being either polar or non-polar.  Polarity: tendency of a molecule, or compound, to be attracted or repelled by electrical.
BONDINGPREVIEW. Bonds Between Atoms Covalent Ionic Polyatomic Ions Metallic Molecular Substance Polar Nonpolar Coordinate Covalent Network Solids What.
Bonding. Energy and Chemical Bonds  Chemical Bond: A force of attraction between atoms in a compound  All elements bond for one reason: to acquire an.
I Chemical Bonding. Chemical Bond  attractive force between atoms or ions that binds them together as a unit  bonds form in order to…  decrease potential.
Bonding IB Chemistry 2 Robinson High School Andrea Carver.
Crux of the Matter Unit 4 Chapters 7 and 8.
Bond types Bond type electron Electronegativity difference IonicDonate/take>1.7 Polar covalent Share Nonpolar covalent Share
A. Ionic Bonding 1. attraction between large numbers of (+) ions and (-) ions 2. results when there is large electronegativity differences 3. generally.
CHEMICAL BONDS Chemical Bond  Mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together.
Chapter 6 Chemical Bonding. Sect. 6-1: Introduction to Chemical Bonding Chemical bond – electrical attraction between nuclei and valence electrons of.
Review – Packet #7  Bonds can be classified as being either polar or non-polar.  Polarity: tendency of a molecule, or compound, to be attracted or repelled.
Polarity Chapter 6.1. Review A covalent bond is formed between two non-metals. Electrons are shared. Orbitals are overlapping.
VSEPR Theory: Molecular Shapes Most shapes are based on a __________________. Examples: CH 4 CCl 4 Removing the top of the tetrahedral makes the ________________.
Chemical Bonding Chapter 11
Unit 6: Chemical Bonding Refer to Ch. 8 & 9 for supplemental reading.
CHEMICAL BONDING. Why do bonds form? To complete the valence or outer energy level Octet Rule – 8 is great! A bond forms when 2 atoms attract the same.
Back Bires 2009 Chapter 6 Chapter 6 Chemical Bonding and Molecular Compounds Ionic bond Ionic bond: Electrons are given or taken, occurs between metal.
Bonding. Introduction to Bonding: Chemical bond: the force that holds two atoms together Bonds may be formed by the attraction of a cation to an anion.
Unit 6: Chemical Bonding Refer to Ch. 8 & 9 for supplemental reading.
Unit 9 Bonding Test Wed. 2/17.
CHAPTER 7 & 8 BONDING. Valence Electrons – the outer most electrons that are involved in bonding Ex. Ion – an atom or group of atoms that has a positive.
Unit 7: Bonding NaCl N2N2 Overview Chemical bonds provide the glue that hold compounds together… In this unit you will learn:  The different types of.
Chapter 12 Ionic Bonding Transfer of electrons Covalent Bonding Sharing of electrons Metallic Bonding Sea of electrons Intermolecular Forces
Chemical Bonding. What is a chemical bond? “attachment” of an atom to another atom.
Bonding. Chemical Bonding Types 1)Ionic 2)Covalent Polar Nonpolar 3)Metallic.
Chemical bonds. Bonding, the way atoms are attracted to each other to form molecules, determines nearly all of the chemical properties we see. Chemical.
Covalent Bond A chemical bond in which electrons are shared. Each atom has access to a full octet (8 electrons). No electrical charges.
Unit 6: Chemical Bonding and Intermolecular Forces
Chemical Bonding 1.
Topic 6 Bonding.
Covalent Bonding Covalent Bond: a bond where atoms share electrons
Chapter 6: Chemical Bonding
Chemical Bonding Chapter 6 Pages
AP Chapters 8-9.
Properties of Molecular Substances
Bonding.
CHEMICAL BONDING Cocaine Chemistry I – Chapter 8
Bonding Chapters 7-8.
UNIT 7: BONDING How can we explain and draw ionic bonds?
Chemical bonding Why do atoms form bonds? Reason 1: Lower energy state
Intramolecular Forces Intermolecular Forces
Station I. Creating Bonds
BONDING Unit 6.
CHEMICAL BONDING IONIC BONDS COVALENT BONDS HYDROGEN BONDS
A. Types of Chemical Bonds
CHEMICAL BONDING IONIC BONDS COVALENT BONDS HYDROGEN BONDS
Covalent Bonds Electrons are shared.
Chapter 6 p Bonding.
Unit 7: Bonding.
Unit 7: Bonding.
UNIT 7: BONDING Why do elements form bonds?
Chapter 6 – Modern Chemistry
IONIC BONDING.
Ionic, Metallic, & Polar Covalent Bonds
Chapter 8 Covalent Bonding.
qotd How many valence electrons do Cl, and Na have?
Molecular Structure and Shape
The Attachment Between Atoms
Chemical Bonding Notes
Chemical Bonding.
Covalent Bonds Electrons are shared.
Presentation transcript:

Bonding

Electronegativity – attraction to another atom’s electrons Chemical Bonds A force of attraction between 2 atoms The “glue” that holds chemical compounds together **Involves VALENCE electrons** Electronegativity – attraction to another atom’s electrons Table S Outer electrons!

3 Types of Bonds Ionic Bonds – metal + nonmetal atoms “transfer of electrons” Electronegativity Difference (E.N.D.) greater than 1.7 Metallic Bonds – metal + metal atoms “sea of electrons” Covalent Bonds – nonmetal + nonmetal atoms “sharing electrons” less than 1.7 Catch! Tug-of-War

Energy of Bonds Exothermic – Energy Released Forming Bonds Atoms are more stable together, and so, RELEASE ENERGY to be at a lower, more stable energy state Endothermic – Energy Absorbed Breaking Bonds Overcome the attraction between the atoms to break a bond, so we ADD ENERGY The stronger the bond, the closer together the atoms are, the more energy is needed to break the bond

X Lewis Dot Structures Use dots to represent electrons Diagram of the valence electrons in an atom or ion Use dots to represent electrons X 3 7 Each consecutive dot will go opposite the one before it, before getting paired up. 1 6 5 2 Octet Rule – 8 Electron Rule Atoms will gain, lose, or share electrons to have 8 valence electrons (except H, He, Li, Be, B) 8 4

Electronegativity Difference E.N.D. > 1.7 One atom is far more electronegative than the other, results in a transfer of electrons 0.4 < E.N.D. < 1.7 One atom is slightly more electronegative than the other, results in an UNEQUAL sharing of electrons E.N.D. < 0.4 Two atoms of equal electronegativity, results in EQUAL sharing of electrons Ionic Bond Polar Covalent Bond Nonpolar Covalent Bond

Ionic Bonding E.N.D. > 1.7 Transfer of electrons Metal + Nonmetal One atom far more electronegative than the other Transfer of electrons Metals give up electrons to nonmetals Metal + Nonmetal Metal (cation) Nonmetal (anion) Lewis Structures Write the neutral atom electron dot structures Draw arrows to show the movement of electrons from metal(s) to nonmetal(s) Draw ion electron dot structures bonded together Na + Cl → [Na]+[ Cl ]-

Ionic Solids – Properties Solid substances formed from ionic bonds Crystalline structure High melting point Dissolve in water (aqueous solution) Don’t conduct heat or electricity as SOLID Conduct electricity as aqueous solutions or liquids

Metallic Bonding 2 or more metal atoms in a sea of electrons Strong bonds form between 2 metals in liquid or solid phase Evidence: high melting & boiling point Properties Conductive of heat & electricity LIQUID SOLID Malleable Ductile High Melting/Boiling Points

Covalent Bonding E.N.D. < 1.7 Sharing of electrons Nonmetal atoms of similar electronegativity will share electrons to complete octets Sharing of electrons Polar Covalent – unequal sharing Nonpolar Covalent – equal sharing

Molecules Smallest unit of a compound made of covalent bonds Exist in all 3 phases of matter (depending on forces of attraction between molecules) Properties Soft Low melting points Do not conduct heat/electricity

sand (silicon dioxide) Molecules Network Solids – bond in a strong network of atoms Have slightly different properties due to the network Harder High melting points Do not conduct heat/electricity (except graphite) Coordinate Covalent Solids – Occur in polyatomic ions One atom donates BOTH electrons to a bond Compounds with polyatomic ions contain BOTH IONIC & COVALENT BONDS!! diamond graphite aesbestos sand (silicon dioxide)

Lewis Structures Add up valence electrons The lowest electronegative element goes in the center (usually there is only 1 atom) Arrange all the other atoms around the central atom Draw a single bond from each outside (terminal) element to the central atom Draw dots to complete octets for outside atoms Add any extra electrons to complete the octet on the central atom If we don’t have enough electrons to complete this octet, make a multiple bond (double or triple) – C, N, O, P, S Count electrons – check for all valence electrons used

Molecule Geometry VSEPR (Valence Shell Electron Pair Repulsion) Electrons want to be as far apart as possible Electron-pair geometry refers to the number of electron pairs surrounding the central atom Molecule geometry refers to Lewis Structures and depends upon both bonding & nonbonding electrons NOTE – double and triple bonds “count” as ONE pair

Molecular Geometry (VSEPR) # Bonds (terminal e- pairs) Examples Shape 1, 2 H—F , O=C=O Linear 3 Trigonal Planar 4 Tetrahedral 5 Trigonal Bipyramidal 6 Octahedral

Molecular Geometry 2 1 Bent 3 Trigonal Pyramidal Linear T-Shaped 4 # Bonding Pairs # Nonbonding Pairs Shape 2 1 Bent 3 Trigonal Pyramidal Linear T-Shaped 4 See Saw 5 Square Pyramidal Square Planar

Molecule Polarity 2 factors affect molecule polarity Bond Polarity If a molecule contains NO polar bonds, it will be nonpolar If a molecule contains polar bonds it could be either polar or nonpolar Molecule Geometry (Shape) If a molecule is symmetrical there is an equal distribution of electrons and so is NONPOLAR If a molecule is asymmetrical there is an unequal distribution of electrons and so is POLAR

Intermolecular Forces Forces of attraction between molecules – based on polarity (a.k.a. Van der Waals Forces) More strongly polar moleculs will have greater Intermolecular Forces (IMFs) Affect melting and boiling points, surface tension, viscosity

Intermolecular Forces Dipole-Dipole Interactions The slightly positive end of one molecule is attracted to the slightly negative end of another Hydrogen Bonding A specific type of dipole interaction where the slightly positive H is attracted to the slightly negative N, O, or F of another

Hydrogen Bonding in Water WATER IS POLAR!!!!! Slightly + H is attracted to Slightly – O