Grade:
11
3 Quarter
Name: -----------------------------
Science
Date: …………………………………………..
Metallic bonding WORKSHEET
PART A: LESSON SUMMARY
Section outline:
1- Describing the Metallic bond.
2- Factors affecting the strength of the Metallic Bond
3- Metallic bond and how it affects properties of metals.
4-Properties of metals
5- Alloys
.
1- Describing the Metallic bond ( The
electron sea model )
1- In a metallic solid , The valence electrons of the metallic atoms are not
held by any specific atom and can move easily between atoms.
2- These valence electrons which are not held by a specific atom are called
delocalized electrons
3- As a result , all the metal atoms in a metallic solid share their valence
electrons to form a “sea” of delocalized electrons
4- This transforms the metal atoms into metal cations ( as they lost their valence electrons to the sea of
electrons )
5- So we now have , Big metal cations ( + ) and a SEA OF DELOCALIZED ELECTRONS ( - )
Metallic Bond : The electrostatic attraction between Positive metal cations and the sea of
delocalized electrons.
2- Factors affecting the strength of the Metallic Bond
1- The nuclear charge ( strength ) of metal cations:
The more powerful the cation is , the more positive it is , the
stronger the metal bond will be.
2- The number of valence electrons ( delocalized
electrons ) :
The more the number of valence electrons , the more negative
the sea of electrons is, the stronger the metal bond will be
3- Metallic bond and how it affects properties of
metals
The main reason for the special properties of metals is the
metallic bond. How?
The metallic bond works to keep the metal atoms in a piece of metal together.
Bonding them together and increasing hardness and compactness.
This compactness gives metals their distinct properties
4- Properties of metals

High melting point  Tungsten has a melting point of 3422 °C  Light bulb filaments are usually made from
tungsten

High boiling point

Malleable  can be hammered into sheets

Ductile  can be drawn into wires

Hard

Conduct electricity  due to existence of electrons
5- Alloys
Definition: An alloy is a mixture of elements that has metallic properties
( Original metal + foreign elements, mixed together )
Properties: The properties of alloys differ somewhat from the properties of the elements they contain.
Example:
STEEL is iron mixed with at least one other element. Some properties of iron are present, but steel has
additional properties, such as increased strength
BRONZE is Copper mixed with Zinc and Tin , it has properties different than properties of the elemnts making
it , kind of a mix.
Types: Substitutional and Interstitial alloys ( they differ in the way the foreign element is introduced to the
original metal )
-
Remember that Metals have a lattice structure similar to that of ionic compounds.
Substitutional alloy
some of the atoms in the original metallic solid are
replaced by other metals of similar atomic size.
Interstitial alloy
small holes (interstices) in a metallic crystal are
filled with smaller atoms.
Atoms of the foreign element are of similar atomic
size to the atoms of the original metal
Atoms of the foreign element are smaller than the
atoms of the original metal
PART B : EXERCISES
A- True or false:
1- In a metallic solid, the inner electrons are delocalized and shared between the atoms of the metal.
2- The metallic bond is the attraction between the sea of electrons and the metallic anions.
3- Delocalized electrons are the electrons of the outer energy level in metal atoms.
4- The more powerful the cation is , the weaker the metallic bond.
5- As the number of valence electrons increase , the metallic properties intensity increase.
6- Metals have high melting points
7- Alloys are the products of chemically mixing two metals together
8- Magnesium is expected to be softer than aluminum
B- Match.
1. Delocalized electrons
2. Metallic bond
3. Covalent bond
4. Ionic bond
5. Alloy
6. Interstitial alloy
7. Substitutional alloy
8. Malleability
9. Ductility
A. a mixture of elements that has metallic properties
B. An alloy in which foreign element atoms are inserted In the
tiny spaces between the original metal’s atoms.
C. The ability of a metal to be hammered
D. The interaction between metal cations and the sea of
electrons they are swimming in.
E. Sharing of electrons between two non metals
F. Electrostatic attraction between a metal ion and a non metal
ion
G. Valence electrons of metals that are not held by a certain
atom
H. An alloy in which the foreign element’s atoms replace the
original metal’s atoms.
I. The ability of a metal to be made into wires
C- State the type of alloy in each of the following pictures.
D- Label the following picture