chemical bonding. remember chemical bonding is a result of valence electrons being gained, lost, or...

Chemical BondingChemical Bonding


Remember Chemical Bonding is a Remember Chemical Bonding is a result of valence electrons being result of valence electrons being gained, lost, or shared between gained, lost, or shared between atomsatoms

There are primarily three types of There are primarily three types of bonding between atoms, ionic bonds, bonding between atoms, ionic bonds, polar covalent bonds, and non-polar polar covalent bonds, and non-polar covalent bondscovalent bonds

Types of BondingTypes of Bonding

The differences in electronegativity The differences in electronegativity reflects the character of bonding reflects the character of bonding between elementsbetween elements


Most atoms have lower potential Most atoms have lower potential energy when they are bonded to energy when they are bonded to other atoms than they have as they other atoms than they have as they are independent particlesare independent particles

What does this mean?What does this mean? It means they “like to be bonded”It means they “like to be bonded”

Covalent BondsCovalent Bonds When two atoms form a covalent bond, When two atoms form a covalent bond,

their their shared electronsshared electrons form form overlapping overlapping orbitalsorbitals

Covalent BondsCovalent Bonds

- water is a polar molecule because oxygen is more electronegative than hydrogen, and therefore electrons are pulled closer to oxygen.

Nobel GasesNobel Gases

Nobel gasses are unreactive because they Nobel gasses are unreactive because they are very stableare very stable

Other atoms do not have completely filled Other atoms do not have completely filled orbitals so they “want” to fill them with orbitals so they “want” to fill them with help from other atoms to become stablehelp from other atoms to become stable

Electron Dot NotationElectron Dot Notation

Electron-dot notation is an electron-Electron-dot notation is an electron-configuration notation in which configuration notation in which only only the valence electrons of an atom of a the valence electrons of an atom of a particular element are shownparticular element are shown indicated by dots placed around the indicated by dots placed around the element symbolelement symbol

Electron Dot-notationElectron Dot-notation

Lewis StructuresLewis Structures

Electron dot notation is used to Electron dot notation is used to represent moleculesrepresent molecules

The pair of dots between the two The pair of dots between the two symbols represents the shared symbols represents the shared electron pair of the hydrogen-electron pair of the hydrogen-hydrogen and fluorine-fluorine hydrogen and fluorine-fluorine covalent bond H:Hcovalent bond H:H

Lewis StructuresLewis Structures

The pair of dots between the two The pair of dots between the two symbols represents the shared pair symbols represents the shared pair of a covalent bondof a covalent bond

The unshared pair, the lone pair, is The unshared pair, the lone pair, is not involved in bonding and belongs not involved in bonding and belongs just to that one atomjust to that one atom

Structural FormulaStructural Formula

The pair of dots represents a shared The pair of dots represents a shared pair of electrons in a covalent bond is pair of electrons in a covalent bond is replaced by a dash: H-Hreplaced by a dash: H-H

A structural formula indicates the A structural formula indicates the kind, number and arrangement, and kind, number and arrangement, and bonds but not the unshared pairs of bonds but not the unshared pairs of the atoms in a molecule:the atoms in a molecule: F-F F-F

H-ClH-Cl

Structural FormulasStructural Formulas

A single covalent bond, or single bond, A single covalent bond, or single bond, is a covalent bond in which one pair of is a covalent bond in which one pair of electrons is shared between two atoms : electrons is shared between two atoms : Example: diatomic hydrogen HExample: diatomic hydrogen H22: H-H: H-H

A double covalent bond, or a double A double covalent bond, or a double bond, is a covalent bond in which two bond, is a covalent bond in which two pairs of electrons are shared between pairs of electrons are shared between two atomtwo atom

Example: diatomic nitrogen NExample: diatomic nitrogen N22: :

Structural FormulasStructural Formulas

A triple covalent bond, or simply a A triple covalent bond, or simply a triple bond, is a covalent bond in triple bond, is a covalent bond in which three pairs of electrons are which three pairs of electrons are shared between two atomsshared between two atoms– Example: ethyne CExample: ethyne C22HH22: :

Multiple bonds, double and triple Multiple bonds, double and triple bonds, have greater bond energies bonds, have greater bond energies and are shared in bond length, they and are shared in bond length, they are STRONG!!are STRONG!!

Drawing StructuresDrawing Structures

1.1. Determine the type and number of Determine the type and number of atoms in the molecules.atoms in the molecules.

For example Draw the Lewis structure For example Draw the Lewis structure of iodomethane CHof iodomethane CH33II

The formula shows 1 Carbon, 3 The formula shows 1 Carbon, 3 Hydrogens, and 1 IodineHydrogens, and 1 Iodine


2. Write the electron-dot notation for each 2. Write the electron-dot notation for each type of atom in the molecule. Place one type of atom in the molecule. Place one electron dot on each side of the element electron dot on each side of the element before pairing any electrons.before pairing any electrons.

Carbon is in group 14, 4 valence electronsCarbon is in group 14, 4 valence electrons

Iodine is in group 17, 7 valence electronsIodine is in group 17, 7 valence electrons

Hydrogen is in group 1, 1 valence electronHydrogen is in group 1, 1 valence electron


3. Determine the total number of 3. Determine the total number of valence electrons available in the valence electrons available in the atoms to be combined.atoms to be combined.

CC 1 x 4e = 4e1 x 4e = 4e

II 1 x 7e = 7e1 x 7e = 7e

3H3H 3 x 1e = 3e3 x 1e = 3e

14e14e


4. If carbon is present, it is the central 4. If carbon is present, it is the central atom, otherwise, the least atom, otherwise, the least electronegative atom is in the electronegative atom is in the center. Hydrogen is never centralcenter. Hydrogen is never central


5. Add unshared pairs of electrons to each 5. Add unshared pairs of electrons to each nonmetal atom (except hydrogen) such nonmetal atom (except hydrogen) such that each is surrounded by eight that each is surrounded by eight electrons.electrons.

Distribute the electron dots so that Distribute the electron dots so that each atom, except for hydrogen, each atom, except for hydrogen, beryllium, and boron, satisfies the octet beryllium, and boron, satisfies the octet rule. Change each pair of dots that rule. Change each pair of dots that represents a shared pair to one dash, represents a shared pair to one dash, two, or three dashes two, or three dashes


6. Count the number of electrons 6. Count the number of electrons surrounding each atom and check surrounding each atom and check the number of valence electrons is the number of valence electrons is the same number you started with the same number you started with in step 3.in step 3.

chemical bonding. remember chemical bonding is a result of valence electrons being gained, lost, or...

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