Notes – Chemical Bonding and Electron Transfer Assign # 30 pt.

Notes – Chemical Bonding and Electron Transfer

Assign # 30 pt.

Chemical Bonding

• Chemical Bonds – Chemical forces which hold atoms together and form complete electrons shells

• Atoms of elements will transfer or share electrons to reach the stable octet number.

Inert (Noble) Gases have 8 valence electrons (2 for He) and are stable

Nonmetals –Groups 5a to 7a will gain electrons to become stable

Metals – Groups 1a to 3a will lose electrons to become stable

Chemical Bonds – Chemical forces which hold atoms together and form complete

electrons shells• Ionic Bond – Positive (+) and

negative (-) ions attract – formed by the transfer of valence electrons.Na 11p+ 11p+

11e- 10e- = +1 Na

Cl 17p+ 17p+17e- 18e- = -1 Cl

Na +1 + Cl-1 = NaCl o

Ionic Bonds

Ion – is an atom or group of atoms that have an electric charge.Atoms become charged when they lose or gain electrons to become stableAtoms which lose electrons become positive (+) Atoms which gain electrons become negative (-)

Ionic Bonds


Na = 11 p+ Na = 11 p+ 11 e - 10 e-

Ionic Bonds


Ionic Bonds


Cl = 17 p+ Cl = 17 p+ 17 e - 18 e-

Ionic Bonds


Na +1 + Cl-1 = NaCl o

Ionic bond

• Atoms which lose electrons become positive (cations)

Lose 1 = +1Lose 2 = +2Lose 3 = + 3• Atoms which gain electrons

become negative (anions)Gain 1 = - 1Gain 2 = - 2Gain 3 = -3

Ionic Bond

• Ionic Bond – a type of chemical bond formed from the attraction of two oppositely charged ions

• Na + plus Cl - combining to form NaCl is an example

Ionic Bond

• Ionic Bond – a type of chemical bond formed from the attraction of two oppositely charged ions

• Na + plus Cl - combining to form NaCl is an example

• A compound consisting of positive and negative ions such as NaCl = sodium chloride is an Ionic Compound

Sodium Chloride

Ionic Compound

Table Salt

Oxidation – Reduction Reactions

Reduction – Any reaction in which a reactant can be considered to gain one or more electrons.

Elements or ions which lose electrons are said to be reduced.

Cu 2+ + 2e- = Cu Copper II ion Copper metal

Reduction Reaction. Copper ions are reduced


Oxidation – Any reaction in which a reactant can be considered to lose one or more electrons.

Elements or ions which gain electrons are said to be oxidized.

Cu = Cu 2+ + 2e- Copper metal Copper II ion

Oxidation Reaction. Copper ions are oxidized






Oil Rig : Oxidation is Loss (of electrons), Reduction is Gain (of electrons)






Oil Rig : Oxidation is Loss (of electrons), Reduction is

Gain (of electrons)Cu + O2 = 2CuO

Copper is OxidizedOxygen is Reduced




Cu = Cu 2+ + 2e-

Copper metal Copper II ionOxidation Reaction. Copper ions are oxidized

Oil Rig : Oxidation is Loss (of electrons), Reduction is Gain

(of electrons)Cu + O2 = 2CuO

Copper is OxidizedOxygen is ReducedCopper loses electronsOxygen gains electrons

• Metals can be changed to ions by oxidation.

• Mg Mg2+ + 2e-

• Metallic ions can be changed to metals by reduction.

• Al3+ + 3e- Al


• Metals and Metal ions will react in a Redox, Reduction-Oxidation reaction.

• The more active metal will react with a less active ion in a replacement reaction

• Cu + Ag+ Ag + Cu+

Cu is oxidized, Ag+ is reducedCu loses an e-, Ag gains an e-


Metallic bonding

• Metal atoms combine in regular patterns in which valence electrons are free to move from atom to atom.

• Most metals have from 1 to 3 valence electrons and are positive ions.

• Metal ions are held in place by a metallic bond an attraction between a positive metal ion and the many electrons surrounding it.

Metallic bonding

• Most metals have from 1 to 3 valence electrons and are positive ions.

• Metal ions are held in place by a metallic bond an attraction between a positive metal ion and the many electrons surrounding it.

Metal Properties

• Metals properties are attributed to the “sea of electrons” flowing over the positive ions

• Malleable and ductile – metal’s positive ions are attracted to electrons and can slide into different positions

Metal Properties

• Luster – When light strikes the valence electrons they absorb it than give it off again

• Electrical and Thermal conductivity – valence electrons move freely and cause electric current to flow or heat to flow easily from hot to cold

1

23 4 5 6 7

8

1

2

3

4

5

6

7

Covalent Bonding

• Covalent Bond – the chemical bond formed when atoms share electrons

• The force holding them together is the attraction of the nucleus and the shared electrons

Covalent Bonding

• Covalent Bond – the chemical bond formed when atoms share electrons


• Usually forms between atoms of nonmetals

Covalent Bonding• Covalent Bond – the

chemical bond formed when atoms share electrons


• Usually forms between atoms of nonmetals

• The neutral group of atoms joined by covalent bonds is called a molecule

Covalent Bonding

• The neutral group of atoms joined by covalent bonds is

called a molecule• Molecular

compounds is a compound composed of covalently bonded molecules

Covalent bonding – Sharing of valence electrons to fill electron shells

• Follows octet rule, except for H and He

• Common elements-

H, C, N, 0

Lines show shared electrons H O

H

H20 – Molecular formula

H OH

- Structural formula – shows the number and position of atoms

O N C

O N C

Show the bonds formed when these atoms combine with Hydrogen (H. )

H20 – Molecular formula

H OH

- Structural formula – shows the number and position of atoms

Show the bonds formed when these atoms combine with each other

H + H =

Cl + Cl =

Br + Br =

Covalent Bonding

• Double bond – Some covalent bonds involve 2 atoms sharing 2 pairs of electrons

• Triple bond – Some covalent bonds involve 3 atoms sharing 2 pairs of electrons

O + O =

Covalent Bonding



O + O =

O + C + O =

Covalent Bonding



O + O =

Covalent Bonding



O + O =

O + C + O =

N + N =

Covalent Bonding

•Triple bond – Some covalent bonds involve 2 atoms sharing 3 pairs of electrons

N + N =

C + O =

Table SaltNaCl- Sodium Chloride

Sugar - glucose

• Abbreviated form of compound showing the element symbols and ratio of atoms

• A subscript shows you the number and ratio of atoms in a compound.

• Ex: Al2O3 = 2 aluminum and 3 oxygen

• Examples-• NaCl• MgCl2

• Li2Cl

• Al2O3

• K2SO4

Chemical formulas

Chemical formulas –• Abbreviated form of compound

showing the element symbols and ratio of atoms

• A subscript shows you the number and ratio of atoms in a compound


• When naming ionic compounds the positive ion comes first, followed by the name of the negative ion

• Examples-• NaCl =• MgCl2

• Li2Cl

• Al2O3

• K2SO4

Types of Matter






• Examples-• NaCl = Sodium Chloride• MgCl2

• Li2Cl

• Al2O3

• K2SO4

Types of Matter






• Examples-• NaCl = Sodium Chloride• MgCl2 =Magnesium

Chloride• Li2Cl

• Al2O3

• K2SO4

Types of Matter







Chloride• Li2Cl = Lithium Chloride

• Al2O3

• K2SO4

Types of Matter








• Al2O3 = Aluminum Oxide

• K2SO4

Types of Matter

Chemical formulas –


• Ions that are made of more than one atom are called polyatomic ions.

• Ex: SO4 = sulfate



• Al2O3 = Aluminum Chloride

• K2SO4 = Potassium Sulfate

Types of Matter





• Examples-• LiCl =• K2S =

• CaF2 =

• MgO2 =

• Na2PO4 =

Types of Matter





• Examples-• LiCl = Lithium Chloride• K2S = Potassium Sulfide

• CaF2 = Calcium Flouride

• MgO2 = Magnesium Oxide

• Na2PO4 = Sodium Phosphate

Types of Matter

Table SaltNaCl- Sodium Chloride

Sugar - glucose

Notes – Chemical Bonding and Electron Transfer Assign # 30 pt.

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