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8/2/2019 What is Periodic Table
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PROJECT OF CHEMISTRYTHE PERIODIC TABLE
4/11/2012
ALI AKBAR
TO MISS AMNA
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Table of Contents
What is periodic table? ......................................................................3
History of Periodic table .....................................................................4
Mendeleevs Periodic Table ...............................................................5
Modern Periodic Table .......................................................................7
Groups ...............................................................................................9
Periods ..............................................................................................9
General Features of Periodic Table ................................................... 10
Classification of General Properties .................................................. 10Metalloids. ...................................................................................... 10
METALS ........................................................................................... 10
Alkali Metals .................................................................................... 11
Alkaline Earth Metals ....................................................................... 11
Non metals ...................................................................................... 12
The Halogens ................................................................................... 12
Transition metals ............................................................................. 13
The noble or inert gases ................................................................... 13
Salient features of Periodic table ...................................................... 15
How elements are placed in periodic table? ..................................... 16
Reference ........................................................................................ 19
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What is periodic table?
The periodic table is a tabular display of the chemical elements,
organized on the basis of their properties. Elements are presented in
increasing atomic number. While rectangular in general outline, gapsare included in the rows or periods to keep elements with similar
properties together, such as the halogens and the noble gases, in
columns or groups, forming distinct rectangular areas or blocks.
http://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Atomic_numberhttp://en.wikipedia.org/wiki/Period_(periodic_table)http://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Noble_gashttp://en.wikipedia.org/wiki/Group_(periodic_table)http://en.wikipedia.org/wiki/Block_(periodic_table)http://en.wikipedia.org/wiki/Block_(periodic_table)http://en.wikipedia.org/wiki/Group_(periodic_table)http://en.wikipedia.org/wiki/Noble_gashttp://en.wikipedia.org/wiki/Halogenhttp://en.wikipedia.org/wiki/Period_(periodic_table)http://en.wikipedia.org/wiki/Atomic_numberhttp://en.wikipedia.org/wiki/Chemical_element8/2/2019 What is Periodic Table
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History of Periodic table
The history of the periodic table reflects over a century of growth in
the understanding of chemical properties, and culminates with the
publication of the first actual periodic table by Dmitri Mendeleev in
1869.While Mendeleev built upon earlier discoveries by such scientists
such as AL-RAZIN and MANDALEEVE.
The table itself is a visual representation of the periodic law which
states that certain properties ofelements repeatperiodicallywhen
arranged by atomic number. The table arranges elements into vertical
columns (groups) and horizontal rows (periods) to display these
commonalities.
http://en.wikipedia.org/wiki/Periodic_tablehttp://en.wikipedia.org/wiki/Dmitri_Mendeleevhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Atomic_numberhttp://en.wikipedia.org/wiki/Atomic_numberhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Dmitri_Mendeleevhttp://en.wikipedia.org/wiki/Periodic_table8/2/2019 What is Periodic Table
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Mendeleevs Periodic Table
Dmitri Mendeleev was a Russian chemist and inventor. He is credited as
being the creator of the first version of the periodic table ofelements.Using the table, he predicted the properties of elements yet to be
discovered.Mendeleev realized that the physical and chemical
properties of elements were related to their atomic mass in a 'periodic'
way, and arranged them so that groups of elements with similar
properties fell into vertical columns in his table.
Gaps and predictions Sometimes this method of arranging elementsmeant there were gaps in his horizontal rows or 'periods'. But instead
of seeing this as a problem, Mendeleev thought it simply meant that
the elements which belonged in the gaps had not yet been discovered.
He was also able to work out the atomic mass of the missing elements,
and so predict their properties. And when they were discovered,
Mendeleev turned out to be right. For example, he predicted the
properties of an undiscovered element that should fit below aluminumin his table. When this element, called gallium, was discovered
in 1875 its properties were found to be close
to Mendeleev's predictions. Two other predicted elements were later
discovered, lending further credit to Mendeleev's table.
http://en.wikipedia.org/wiki/Chemistryhttp://en.wikipedia.org/wiki/Periodic_tablehttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Periodic_tablehttp://en.wikipedia.org/wiki/Chemistry8/2/2019 What is Periodic Table
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Modern Periodic Table
Our modern day periodic table is expanded beyond Mendeleev's initial
63 elements. Most of the current periodic tables include 108 or 109
elements. It is also important to notice how the modern periodic tableis arranged. Although we have retained the format of rows and
columns, which reflects a natural order, the rows of today's tables show
elements in the order of Mendeleev's columns. In other words the
elements of what we now call a "period" were listed vertically by
Mendeleev. Chemical "groups" are now shown vertically in contrast to
their horizontal format in Mendeleev's table. Note also that
Mendeleev's 1871 arrangement was related to the atomic ratios in
which elements formed oxides, binary compounds with oxygen;
whereas today's periodic tables are arranged by increasing atomic
numbers, that is, the number of protons a particular element contains.
Although we can imply the formulas for oxides from today's periodic
table, it is not explicitly stated as it was in Mendeleev's 1871 table. The
oxides ratio column was not shown in earlier Mendeleev versions.
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Groups
Group is a vertical column of elements in the periodic table with the
same number of valence electrons.
The modern periodic table of the elements contains 18 groups, or
vertical columns. Elements in a group have similar chemical and
physical properties because they have the same number of outer
electrons. Elements in a group are like members of a family--each is
different, but all are related by common characteristic
Periods
Period is the horizontal row of elements in the periodic table. Table
with the period number including the numbers of valence electron
shells. Along a period, a gradual change in chemical properties occurs
from one element to another. For example, metallic properties
decrease and nonmetallic properties increase as you go from left to
right across a period. Changes in the properties occur because the
number of protons and electron increases from left to right across aperiod or row. The increase in number of electrons is important
because the outer electrons determine the element's chemical
properties.
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General Features of Periodic Table
Classification of General Properties
The general properties of elements allow them to be divided into threeclassifications: metals, nonmetals and
Metalloids
The distribution of metals is shown in your periodic table as boxes
colored yellow, purple and two shades of blue. Metalloid elements are
in the diagonal boxes colored pink and nonmetal elements are above
the diagonal line to the right of the metalloids, in boxes colored green,gold, and red. Notice that hydrogen's box is colored green, even
though it is at the top of a group of metals.
METALS
As you can see, the vast majority of the known elements are metals.
Many metals are easily recognized by non-chemists. Common
examples are copper, lead, silver and gold. In general, metals have a
luster, are quite dense, and are good conductors of heat and electricity.
They tend to be soft, malleable and ductile (meaning that they are
easily shaped and can be drawn into fine wires without breaking). All of
these properties are directly related to the fact that solid metals are
crystals formed from positive ions surrounded by mobile electrons.
This mobility allows electrons to absorb and reflect light in many
wavelengths, giving the metals their typical luster The Group I Alkali
Metals and the Group II Alkaline Earths have more metallic
characteristics than elements farther right whose square are colored
blue.
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Alkali Metals
The alkali (IA) metals show a closer relationship in their properties than
do any other family of elements in the periodic table. Alkali metals are
so chemically reactive that they are never found in the element form innature. All these metals react spontaneously with gases in the air, so
they must be kept immersed in oil in the storeroom. They are so soft
that they can be cut with an ordinary table knife, revealing a very
"buttery", silvery metal surface that immediately turns dull as it reacts
with water vapor and oxygen in the air. The chemical reactivity of alkali
metals increases as the atomic number increases.
Alkaline Earth Metals
The alkaline earth (IIA) metals also exhibit the typical metal
characteristics of high density, metallic luster and electrical and thermal
conductivity. Rocks and minerals containing silica, magnesium, and
calcium compounds are widely distributed. These chemicals are also
abundant as compounds in sea water. Their chlorides are abundant in
sea water. Radium, the largest of the alkaline earths, is a radio active
element that occurs naturally only in very small quantities. Chlorophyll,
the green coloring in plants, is a magnesium-containing compound.
Calcium is a major component of animal bones, teeth and nerve cells.
Alkaline earth elements form compounds by losing, or in the case of
beryllium, sharing two electrons per atom. These atoms hold their
electrons more tightly than alkali metals. They are, therefore, smaller
than and not so chemically reactive as the neighboring alkali metals.
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Non metals
Nonmetal, or non-metal, is a term used in chemistry when classifying
the chemical elements. On the basis of their general physical and
chemical properties.
There is no rigorous definition for the term "nonmetal" - it covers
a general spectrum of behavior. Common properties considered
characteristic of a nonmetal include:
poor conductors of heat and electricity when compared to metals
they form acidic oxides (whereas metals generally form basic
oxides) in solid form, they are dull and brittle, rather than metals which
are lustrous, ductile or malleable
usually have lower densities than metals
they have significantly lower melting points and boiling points
than metals (with the exception of carbon)
Non-metals have high electro negativity.
The Halogens
The halogens or halogen elements are a series of nonmetal elements
from Group 17 IUPAC Style (formerly: VII, VIIA) of the periodic table,
comprising fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and
astatine (At). The artificially created element 117, provisionally referred
to by the systematic name ununseptium, may also be a halogen.The
group of halogens is the only periodic table group which contains
elements in all three familiar states of matter at standard temperature
and pressure.
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Transition metals
The transition elements are also known as the transition metals. These
elements are very hard, with high melting points and boiling points.
Moving from left to right across the periodic table, the five d orbitalsbecome more filled. The d electrons are loosely bound, which
contributes to the high electrical conductivity and malleability of the
transition elements. The transition elements have low ionization
energies. They exhibit a wide range of oxidation states or positively
charged forms. The positive oxidation states allow transition elements
to form many different ionic and partially ionic compounds.
The noble or inert gases
The noble gases are a group of chemical elements with very similar
properties: under standard conditions, they are all odorless, colorless,
monatomic gases, with very low chemical reactivity. The six noble gases
that occur naturally are helium (He), neon (Ne), argon (Ar), krypton (Kr),
xenon (Xe), and the radioactive radon (Rn). The properties of the noble
gases can be well explained by modern theories of atomic structure:
their outer shell of valence electrons is considered to be "full", giving
them little tendency to participate in chemical reactions, and it has only
been possible to prepare a few hundred noble gas compounds. The
melting and boiling points for each noble gas are close together,
differing by less than 10 C (18 F); consequently, they are liquids over
only a small temperature range.
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Salient features of Periodic table
The grouping of elements with similar properties together and the
separation of elements with dissimilar properties is known as
classification of elements. The table, which classifies elements onthe basis of their properties, is called the periodic table.
The earliest classification was into metals and non-metals, which
was on the basis of physical and chemical properties.
According to Mendeleev's periodic law, the physical and chemical
properties of elements are periodic functions of their atomic mass
Mendeleev was able to predict the existence of undiscovered
elements
Mendeleev corrected the atomic masses of a few elements on the
basis of their positions in the periodic table
Mendeleev's table could not assign a proper position to hydrogen
or to the lanthanides and actinides and isotopes
Modern periodic law states that the properties of elements are
periodic functions of their atomic numbers. It is based on
electronic configuration of the elements
The vertical columns are called groups, while the horizontal rows
are called periods
There are 7 periods and 8 groups subdivided into 18 sub groups
Group number is number of electrons in the valence shell.
Elements having the same valence number are grouped together. The number of shells present in the atom gives period number
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How elements are placed in periodic table?
As stated last section, the periodic table organizes the elements
according to general patterns of similarity. Below is a very small image
of the periodic table. It is basically unreadable in terms of specificinformation, but it allows us to easily look at the periodic tables
structure general trends. The vertical columns of the periodic table
(marked by yellow stripes in the figure) are called groups. The
horizontal rows are called periods. There are 18 groups and 7 periods.
In discussing the periodic table from here on out we will use the terms
group and period. Down a group means moving from top to bottom;
across a period means moving from left to right.
Reading the Periodic Table: Carbon
To describe the information contained within each individual box we
will use a specific example: carbon.
Figure %: Description of Carbon on the Periodic Table
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Element Name
The purpose of the element name is obvious. However, many Periodic
Tables do not include element names. For those situations you must
memorize the symbols that accord to each element name.
Element Symbol
Each element has a specific one or two letter symbol that is used
interchangeably with its name. These should be memorized. Most of
the time, symbols quite clearly accord to the name of the element they
represent, as C accords to carbon. Occasional, however, an element's
name and symbol have little relation. For example, the symbol for
mercury is Hg.
As you move across a period the atomic number increases. Similarly, as
you move down a group the atomic number increases. In this way, the
atomic number represents exactly where in the periodic table an
element stands.
More importantly, and the reason why the ordering of the elements
according to atomic number yields elements in groups with similar
chemical and physical properties, the atomic number is the same as the
number of protons in the nucleus of an atom of an element, and also
the same as the number of electrons surrounding the nucleus in a
neutral state. Carbon, for example, has six protons and six electrons.
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Atomic Mass
Along with protons, an atom also contains neutrons in its nucleus. The
atomic mass (also called atomic weight) of an element is the combined
number of protons and neutrons in the nucleus.
Atoms of particular elements generally have different "versions,"
meaning that elements have atoms with different numbers of neutrons
in their nucleus. These different versions are called isotopes. The
atomic weight displayed is actually the weighted average of the mass
numbers of the various isotopes. The atomic weight for Carbon is 12.01
because around 99% of all carbon is the carbon-12 isotope.
Simple Periodic Trends
Atomic Number
The Atomic number increases from the top left to the bottom right. It
ascends sequentially across each period.
Atomic Weight
Weight The atomic weight of the elements generally increases as you
move down a group and across a period. Hydrogen, at the top left of
the table, is the lightest element. The unnamed element 112 is the
heaviest. There are some instances when this rule does not hold true,
however. For instance, because it has a high percentage of isotopes
with many neutrons, the atomic weight of tellurium (Te) is higher than
that for iodine (I), even though iodine has a higher atomic number.
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Reference
http://www.sparknotes.com/chemistry/fundamentals/period
ictable/section2.rhtml
www.chemicool.com/
http://en.wikipedia.org/wiki/Periodic_table
http://www.lenntech.com/periodic/history/history-periodic-
table.htm
http://www.sparknotes.com/chemistry/fundamentals/periodictable/section2.rhtmlhttp://www.sparknotes.com/chemistry/fundamentals/periodictable/section2.rhtmlhttp://www.chemicool.com/http://en.wikipedia.org/wiki/Periodic_tablehttp://www.lenntech.com/periodic/history/history-periodic-table.htmhttp://www.lenntech.com/periodic/history/history-periodic-table.htmhttp://www.lenntech.com/periodic/history/history-periodic-table.htmhttp://www.lenntech.com/periodic/history/history-periodic-table.htmhttp://en.wikipedia.org/wiki/Periodic_tablehttp://www.chemicool.com/http://www.sparknotes.com/chemistry/fundamentals/periodictable/section2.rhtmlhttp://www.sparknotes.com/chemistry/fundamentals/periodictable/section2.rhtml