Higher and foundation tiers
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 called the transition metals is where most of the metals are found. Looking at the periodic table below you can see that around 75 percent of the elements are metals.
The physical properties of an element; that is properties such as melting points, boiling points and densities
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.
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:
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, so the metal atoms will form metal
ions with a charge of +1. As you go down a group in the periodic table such as the 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 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.
There are exceptions to this broad rule. 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 typically 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.
