Chemical bonding

CHEMICAL BONDING

IONIC BONDS COVALENT BONDS HYDROGEN BONDS

IONIC BONDING

When an atom of a nonmetal takes one or more electrons from an atom of a metal so both atoms end up with eight valence electrons

IONIC BONDING

IS THE COMPOUND AN IONIC COMPOUND?
METAL
NONMETAL
SUBSCRIPTS

IONIC BOND FORMATION

Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets.



IONIC BONDING
ION – any atom with more orless electrons that it issupposed to have* *Remember that the number of electrons is supposed to be equal to the number of Protons if the atom has a neutral charge

IONIC BONDING

Metals will tend to lose electrons and become POSITIVE CATIONS
Normal sodium atom
loses one electron
to become sodium ion

IONIC BONDING

Nonmetals will tend to gain electrons and become NEGATIVE ANIONS
Normal chlorine atom
gains an electron
to become a chloride ion

Na+1 is called a sodium ion The +1 symbol means it has lost one electron

IONIC BONDING

Mg+2 is called a magnesium ion The +2 symbol means it has lost two electron

IONIC BONDING

S-2 is called a sulfide ion The -2 symbol means it has gained two electron

IONIC BONDING

Cl-1 is called a chloride ion The -1 symbol means it has gained one electron

IONIC BONDING


POLYATOMIC IONS--a group of atoms that act like one ion NH4+1 ammonium ion CO3-2 carbonate ion PO4-3 phosphate ion
IONIC BONDING

POLYATOMIC IONS ACT JUST LIKE ANY OTHER NEGATIVE ION WHEN BONDING

IONIC BONDING



IONIC BONDING
SODIUM SULFATE

IONIC BONDING

Properties of Ionic Compounds
Crystalline structure. A regular repeating arrangement of ions in the solid. Ions are strongly bonded. Structure is rigid. High melting points- because of strong forces between ions.

Crystalline structure

+
+
+
+
+
+
+
+
+
-
-
-
-
-
-
-
-
-
The POSITIVE CATIONS stick to the NEGATIVE ANIONS, like a magnet.

COVALENT BONDING

When an atom of one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

COVALENT BOND FORMATION

When one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

COVALENT BONDING

IS THE COMPOUND A COVALENT COMPOUND?
NONMETAL
NONMETAL
YES since it is made of only nonmetal elements

Covalent bonding

Fluorine has seven valence electrons
F



Covalent bonding
Fluorine has seven valence electrons A second atom also has seven
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals
F
F

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals
F
F
8 Valence electrons

Covalent bonding

Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals
F
F
8 Valence electrons

Single Covalent Bond

A sharing of two valence electrons.Only nonmetals and Hydrogen.Different from an ionic bond because they actually form molecules.Two specific atoms are joined.In an ionic solid you can’t tell which atom the electrons moved from or to.

How to show how they formed

It’s like a jigsaw puzzle.I have to tell you what the final formula is.You put the pieces together to end up with the right formula.For example- show how water is formed with covalent bonds.

Water

H
O
Each hydrogen has 1 valence electron Each hydrogen wants 1 more The oxygen has 6 valence electrons The oxygen wants 2 more They share to make each other happy

Water

Put the pieces together The first hydrogen is happy The oxygen still wants one more
H
O

Water

The second hydrogen attaches Every atom has full energy levels
H
O
H

Multiple Bonds

Sometimes atoms share more than one pair of valence electrons. A double bond is when atoms share two pair (4) of electrons. A triple bond is when atoms share three pair (6) of electrons.

Carbon dioxide

CO2 - Carbon is central atom ( I have to tell you) Carbon has 4 valence electrons Wants 4 more Oxygen has 6 valence electrons Wants 2 more
O
C

Carbon dioxide

Attaching 1 oxygen leaves the oxygen 1 short and the carbon 3 short
O
C

Carbon dioxide

Attaching the second oxygen leaves both oxygen 1 short and the carbon 2 short
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more
O
C
O

Carbon dioxide

The only solution is to share more Requires two double bonds Each atom gets to count all the atoms in the bond
O
C
O

Carbon dioxide

The only solution is to share more Requires two double bonds Each atom gets to count all the atoms in the bond
O
C
O
8 valence electrons

Carbon dioxide

The only solution is to share more Requires two double bonds Each atom gets to count all the atoms in the bond
O
C
O
8 valence electrons

Carbon dioxide

The only solution is to share more Requires two double bonds Each atom gets to count all the atoms in the bond
O
C
O
8 valence electrons

Examples

NH3 N - has 5 valence electrons wants 8 H - has 1 valence electrons wants 2 NH3 has 5+3(1) = 8 NH3 wants 8+3(2) = 14 (14-8)/2= 3 bonds 4 atoms with 3 bonds
N
H



N
H
H
H
Examples
Draw in the bonds All 8 electrons are accounted for Everything is full


HCN
Put in single bonds Need 2 more bonds Must go between C and N
N
H
C


HCN
Put in single bonds Need 2 more bonds Must go between C and N Uses 8 electrons - 2 more to add
N
H
C



HCN
Put in single bonds Need 2 more bonds Must go between C and N Uses 8 electrons - 2 more to add Must go on N to fill octet
N
H
C

Structural Examples

H C N
C O
H
H
C has 8 electrons because each line is 2 electrons Ditto for N Ditto for C here Ditto for O

Polar Bonds

When the atoms in a bond are the same, the electrons are shared equally. This is a nonpolar covalent bond. When two different atoms are connected, the atoms may not be shared equally. This is a polar covalent bond. How do we measure how strong the atoms pull on electrons?

How to show a bond is polar

Isn’t a whole charge just a partial charged+ means a partially positived- means a partially negativeThe Cl pulls harder on the electronsThe electrons spend more time near the Cl H
Cl
d+
d-

Polar Molecules

Molecules with ends

Polar Molecules

Molecules with a positive and a negative end Requires two things to be true The molecule must contain polar bonds This can be determined from differences in electronegativity. Symmetry can not cancel out the effects of the polar bonds. Must determine geometry first.

Is it polar?

HF H2O NH3 CCl4 CO2

Hydrogen bonding

Are the attractive force caused by hydrogen bonded to F, O, or N. F, O, and N are very electronegative so it is a very strong dipole. The hydrogen partially share with the lone pair in the molecule next to it. The strongest of the intermolecular forces.

Hydrogen Bonding

H
H
O
d+
d-
d+
H
H
O
d+
d-
d+

Hydrogen bonding

H
H
O
H
H
O
H
H
O
H
H
O
H
H
O
H
H
O
H
H
O