METALS,
METALLOIDS AND NON –METALS
Apart from grouping the elements using their blocks,
we can also group elements on periodic table into metals, metalloids and non
metals.
Metals: these are elements that can give away
electrons to become positively charged, they can conduct heat and electricity. They
are located between group 1 to 13 of the periodic table. That is from group sodium
to aluminium. (see the table above).
Non- metals: these are elements that do accept
electron from other elements in order to complete their outermost shell. They do
not conduct electricity and heat. They are found between group 14 to 18.ofthe
periodic table. That is from carbon to the noble gasses.
Metalloids: these are elements that their characteristics
are intermediate between metals and non metals. That is are not completely
metals nor complete non-metals in their behaviour. They are found between group
12 to 16 of the periodic table. (see the image above for clarifications).
GROUP
AND PERIODS OF ELEMENTS
The most popular and main classification of the
periodic table is the group and period. Elements are classified into groups based
on the number of electrons they have on their outer most shell while they are
also classified into periods based on the number of shells they have. All elements in a particular group have the
same number of electrons in their outer most shell and all elements in a particular periods have
the same number of shell. The group is the vertical column of the periodic table
while the horizontal row is the period. There are 8 groups and seven periods on
the modern periodic table.
GROUPS
AND THEIR PROPERTIES
GROUP
ONE ELEMENTS
1. They
include H, Li, Na, K, Rubidium, Caesium
and Francium
2. They
are called alkaline metal
3. They
have 1 electron in their outermost
shell
4. They
are all metals which are strongly electropositive except for hydrogen which is
a gas but have the atomic number of 1.
5. They
are readily ionized by loss of the single valence electron to become a
uni-positive ion.
6. They
are very reactive and form very stable electrovalent compounds
7. They
are good reducing agents
GROUP
TWO ELEMENTS
1.
They include Be, Mg,
Ca, Sr, Ba and Ra
2.
They are also called alkaline
earth metal
3.
They have two valence
electrons and ionize by the loss of the two valence electrons to form bivalent
ions
4.
They are all metals but
less reactive than group one elements. Their reactivity increases down the group
5.
They are good reducing
agents.
GROUP
THREE ELEMENTS
1.
They include B, Al, Ga,
In and thallium
2.
They have three
electrons in their outermost shell
3.
They form weakly
electrovalent compounds with Non-metal
4.
Boron is a non- metal,
forming covalent bond while Aluminium is a metal.
GROUP
FOUR ELEMENTS
Group
4 elements are quite mixed. Metallic properties increases down the group,
while carbon is a non –metal, Silicon and Germanium are metalloids, Tin and
Lead are metals.
However,
both Silicon and Lead form amphoteric oxides.
Group five elements
This
the Nitrogen family, Nitrogen is a gas at room temperature, Phosphorus is a
solid, while Antimony and Bismuth are metals.
GROUP
SIX ELEMENTS
1. This
group also include both non-metals and metals.
2. Oxygen
and Sulphur are non-metals while Selenium and Tellurium are metals.
GROUP
SEVEN ELEMENTS
1. They
are popularly known as HALOGENS
2. They
include Fluorine, Chlorine, Bromine, Iodine and Astatine.
3. They
are highly electronegative
4. They
have seven electrons in their outer most shell.
5. Their
electronegativity decreases down the group. However, Fluorine is most
Electronegative Element and the most reactive of all the elements.
GROUP
EIGHT ELEMENTS:
1. They
are called the noble gases
2. They
are all gas at room temperature
3. They
include, Helium, Neon, Argon, Krypton, Xenon and Radon
4. They
have completely filled shell and hence, they are all unreactive.
TRANSITION
ELEMENTS
Between group 2 and 3 is a block of elements which
shows similar and strange behaviour the other metals. They are called the transition
elements. They are all metals with metallic properties. Their strange behaviour
include:
1. Variable
oxidation state
2. Paramagnetic
in nature
3. Formation
of coloured compound
4. Catalytic
ability.
5. They
include: Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel,
Zinc.
LANTHANIDE
AND ACTINIDE
Apart
from the various groups of elements discussed so far, there are set of another
element isolated below the periodic table. They are originally located between
period six and seven. These elements are called the lanthanide and the actinide
series respectively. (See the table above) they start from Lanthanum to
Lawrencium.
