The periodic table below has been split into 2 parts. The right-hand side of the
table is where
the non-metals are found in groups 3, 4, 5, 6, 7 and 0. The left-hand side is where you
find the metals in
groups 1 and 2 and the centre block of the periodic table; which is where the transition metals are found. Looking at the periodic table below you can see that around 75 percent of the elements are metals.
Properties of metals
The physical properties of an element; that is properties such as its melting point, boiling point and density depend to a large extent on the type of bonding present in the element and on its structure.
Metals
all have a giant structure of metal ions with all the ions held together by strong metallic bonds.
The metallic bonds present in metals are due to the attraction of the delocalised negatively charged electrons and the positively charged metal ions. These metallic bonds are strong. A giant
structure with lots of strong metallic bonds will result in metals with high melting and boiling points.
Physical properties of metals
You should be explain and describe the common physical properties of metals and explain how these relate to the structure and bonding found in metals. These properties include:
Metals are also good conductors of heat and electricity due to the delocalised electrons present within their structure. These delocalised electrons also reflect light giving many metals their lustre or "shiny" appearance.
The ions present
in most metals are tightly packed together so metals will be dense.
Metals are malleable and ductile. Malleable means that they can be beaten and hammered into different shapes, a blacksmith for example would use this property of metals when he is shaping metals in various objects such as gates and tools. The layers of metal ions
present in the giant metallic structure are able to move and slide over each other when a force is applied to them; as outlined in the image below.
The metallic bonds break but reform instantly when the layers stop moving. Other types of giant structures such as ionic lattices and giant covalent structure simply break if a large enough pushing force is applied to them because unlike in a metallic giant structure the ions or atoms present are not able to slide over each other in these structures.
If a metal is described as ductile then it can be drawn into wires; gold, platinum, copper are examples of metals which are very ductile.
Metal cables and wires can support large heavy loads before they break; that is they are strong in tensions. This is simply because they consist of giant structures with lots of strong metallic bonds present.
Some metals are sonorous; this means they make a ringing noise when struck. Silver is a particularly sonorous metals whereas soft metals such as lead are not sonorous.
Iron, nickel and cobalt are the only three metals which are magnetic. Many alloys are also magnetic; such a steel but this simply because they contain one of the three magneticmetals.
The images below summarise the main physical properties of metals:
Chemical properties of metals
The chemical properties of elements; that is how they react with other substances depends on the number of electrons
in their last shell. This is also related to the position of the element in the
periodic table. Elements
react in such a way as to achieve full last electron shells. That is 2 electrons in the case of the
first electron shell and 8 electrons for all other shells. Atoms achieve full shells by losing or
gaining or even sharing electrons.
Metals always lose electrons
when they react e.g. sodium an
alkali metal in group 1 of the periodic
table has an electron arrangement of 2,8,1. To achieve a full last shell it can either gain 7
electrons
or lose 1 electron. Since gaining 7 electrons is not possible it will simply lose
one electron to form a
charged atom or ion with a charge of +1.
All alkali metals in group 1 will lose 1 electron
when they react. This explains why the alkali metals all react in a similar way. When a metal atom loses one electron it will form a metal
ion with a charge of +1.
As you go down a group in the periodic table such as the group I alkali
metals from Li, Na, K, Rb, Cs the atoms
get larger as more electron shells are added, so the negatively charged
electrons in the last shell are
further away from the attraction of the
positively charged nucleus and the electron in the last shell is also
shielded or screened
from the protons in the positively charged
nucleus by the addition of extra electron shells, this means that less energy is required to remove the
outer electron as more shells are added. So the electron in the last shell
will require much less energy to remove it. This means that the metals become more reactive as you descend the group.
A similar argument can be made for the metals in group 2 and 3 of
the periodic table, but remember metals in
group 2 will lose 2 electrons and form ions
with a 2+ charge and group 3 metals will lose 3 electrons to form
ions with a 3+ charge.
No rules are perfect!
The alkali metals at the top of group 1 all float on
water and so these metals have low
densities.
The melting and boiling points of group 1 metals are generally much lower that you might expect
from a typical metal. The metals in group 1 are not typical of
what most people think of as metals.
The transition metals (shown in red in the periodic table above) on the other hand are hard, strong,
shiny metals that are excellent conductors of electricity and heat. These
metals are what most think
of as a typical metal.
Click on the flashcards below to review the basic properties of metals
Metals are malleable, this means they can be......
Hammered, pressed, rolled and beaten into various shapes without breaking.
The three magnetic metals are:
iron, cobalt and nickel are magnetic metals.
Metals are described as ductile, what does this mean?
Dutile means they have the ability to be drawn or stretched into thin wires without breaking
What are the key features of a metallic bond?
A metallic bond is the strong electrostatic attraction between positively charged metal ions and a "sea" of freely moving, delocalised electrons.
What properties make the alkali metals different from most other common metals?
Alkali metals are soft, reactive metals with low melting and boiling points.
When metals react they tend to lose their outer valency electrons, what will they form?
Metals tens to lose electrons when they react with non-metals to form positively charged ions.
Why are metals good electrical conductors?
Metals contain a sea of delocalised electrons which is able to move and carry an electrical current.
Why are metals good thermal conductors?
When one part of a metal is heated, the electrons in that area gain kinetic energy, they then collide with other electrons and metal ions, transferring this energy rapidly throughout the rest of the metal.
Why do metals have high melting and boiling points?
A large amount of energy is needed to break the strong metallic bonds bonds present in metals.
Why are metals dense?
The metals ions present in a metallic structure are closely packed together with not much space between them, this results in a high mass per unit volume.
Key Points
Around 75% of the elements in the
periodic table are metals.
The metals are found on the left-hand side
of the periodic table.
Metals have a giant structure with lots of strong metallic bonds holding this structure together
Metals are:
strong in tension: support a heavy load before they break.
good conductors of heat and electricity.
generally metals have high melting points
malleable: can be hammered and beaten into different shapes
metals are shiny, they reflect light.
iron, cobalt and nickel are the only three magnetic metals.
metals lose their outer shell
electrons when they react to ions with a
positive charge.
The physical properties of an element; that is properties such as its melting point, boiling point and density depend to a large extent on the type of bonding present in the element and on its structure.
Metals
all have a giant structure of metal ions with all the ions held together by strong metallic bonds.
