Properties of metals

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1. Properties of metals and metallic bonding Page 1
Properties of metals and metals metallic bonding
Characteristics of metals
Metals are shiny, malleable, ductile and good conductors of heat and
electricity. The structure of metals and the nature of metallic bonds explain some of
these typical features. Metals are made up of positive ions closely packed together in
crystalline solids. The positive ions are surrounded by a mobile sea of electrons.
These valence electrons are free to move away from their atoms of origin. When one
electron flows away, another one moves into take its place, due to the electrostatic
attraction between the cat ions and the electrons. This is the nature of metallic
bonding what holds a metal together. Compare this image of a collection of cations
surrounded by a mobile sea of electrons with ionic bond, where oppositely charged
ions are held together by electrostatic force of attraction, or covalent bonds, where
two uncharged atoms share their valence electrons. Metallic bonds are much weaker
than either ionic or covalent.

2. Properties of metals and metallic bonding Page 2
Why are metals shiny?
The highly mobile sea of electrons are partially responsible for the shininess of
metals – photons of light are more readily absorb by free electrons, which can easily
jump to a higher energy level. The energy is re-emitted as light. The colour of the
metal is determined by the wavelength of light which is re- emitted.
Why are metal good conductors of heat and electricity?
Similarly this free flow of electrons explains the ability of metals to conduct heat and
electricity. When you heat up a metal, the free electrons quickly start vibrating.
Increased kinetic energy means increased temperature.
When an electric current is applied to a metal, electrons enter from one side, causing
repulsion and generating movement within the sea of electrons, and an equal
number of electrons exit the metal as the number that is entered.

Why are metals malleable?
The mobile sea of electrons also explains the malleable nature of metals. If you
strike an ionic crystal with a hammer, it shatters. (Smash into fragments). This is
because the applied force pushes like ions close together. They violently repel each
other, breaking the crystal apart. In contrast, if you hit a metal with a hammer it
doesn’t break – it just dents. (form a cavity/ set back/ reduce in thickness) Metals are
able to deform in response to an applied force. The mobile sea of electrons shields
the cations from each other, preventing violent repulsion and allowing the metal to
change shape. The most malleable metal is gold.

3. Properties of metals and metallic bonding Page 3

Why metals are ductile?
A similar property to the malleability of the metal is their ability to be pulled into long
thin wires. We call this ductility. Ionic compound are not ductile for the same reason
they are not malleable in general – if an ionic compound is forced into a long
cylinder, it breaks apart because of the repulsion of like ions. In contrast, a metal can
be pulled into a long cylindrical shape, shielded from each other because the cations
can line up, shielded from each other as the fluid like sea of electrons flow around
them. The most ductile metal is platinum.
Almost all the metals are solid at room temperature, the cat ions forming a
recognizable, tightly packed shape. Can you think of an exception? Mercury is the
only metal that is liquid at room temperature.
Why are metals sonorous?
Meaning of sonorous:
 capable of giving a deep, resonant sound
 makes a ringing sound when hit
Electron bonding in metals is highly delocalized (due to very low electronegativity).
This means that when hit, the electron cloud moves extremely easily - there is very
little energy dissipated. This allows the incoming kinetic energy to be easily
propagated as a form of disequilibrium (wave).
P.S :- this is not in all metals - it is in sheet metals, and they have to be of relatively
low density. High-density metals will not as easily propagate the kinetic energy, due
to additional atomic collisions damping the effect.

4. Properties of metals and metallic bonding Page 4
Why metals are having high melting and boiling points?
The force of attraction between the metal ion and delocalized electrons are strong. More energy is
needed to overcome the force by melting or by boiling.

In chemistry, a metal is an element that readily loses electrons to form positive ions
(cations) and has metallic bonds between metal atoms.
Properties of metals
Strong
Malleable and ductile
Sonorous
Good conductors of heat and electricity
High melting and boiling point