1. República Bolivariana de Venezuela.
Ministerio del poder Popular para la Educación Universitaria.
IUPSM Santiago Mariño.
Mérida.
Integral:
Eri Araque 20832039
Chemical ing 49
Technical English
Teacher: Aracelis Torres
June, 2013

2. Index
Introduction
Periodic Table: History, Discovery of elements, Notion of
element and periodic properties, Structure and
organization of the periodic table.
Acids and Bases
Conclusion
bibliography
Periodic table diagram

3. Introduction
The periodic table has become so familiar that it is part of the materials
for any student, especially for students of chemistry, medicine and engineering.
Of the periodic table is obtained necessary information to the chemical
element, as regards the internal structure and properties, either physical or
chemical.
The current modern periodic table explains in detail and updated the
properties of chemical elements based on their atomic structure.
According to their chemical properties, elements are classified into
metals and non-metals. There are more non-metallic metal elements. The same
elements that are in earth exist on other planets in outer space. The student
must know both kinds, physical and chemical properties important, not
memorize, but familiar, and familiar with such as the valence of the main
metallic and nonmetallic elements, not alone or isolated, but by groups or
families (I , II, III, etc.) and thereby learn in an easy and flexible formulas and
chemical names, which is a vital part of the language of chemistry.

4. History
The history of the periodic table is closely related to various aspects of
the development of chemistry and physics:
• The discovery of the elements of the periodic table.
• The study of the common properties and the classification of the elements.
• The notion of atomic mass (initially called 'atomic weight ") and, later, and in
the twentieth century, atomic number.
• The relationships between the atomic mass (and, later, the atomic number)
and periodic properties of the elements.
Discovery of elements
Although some elements such as gold (Au), silver (Ag), copper (Cu), lead
(Pb) and mercury (Hg) were known from antiquity, the first scientific discovery of
an element occurred in the seventeenth century when the alchemist Hennig
Brand discovered phosphorus (P). In the eighteenth century met many new
elements, the most important of which were the gases, with the development of
pneumatic chemistry: oxygen (O), hydrogen (H) and nitrogen (N).
Also consolidated in these years the new concept of element, which led
to Antoine Lavoisier to write his famous list of simple substances, which listed
33 items. In the early nineteenth century, the application of the electric battery
to the study of chemical phenomena led to the discovery of new elements, such
as alkali metals and alkaline earth metals, especially through the work
deHumphry Davy. In 1830, 55 elements were known. Then in mid-nineteenth
century, with the invention of the spectroscope, new elements were discovered,
many of whom are appointed by the color of their characteristic spectral lines:
cesium (Cs, from Latin caesius, blue), thallium (Tl, stem, by its green color),
rubidium (Rb, red), and others.
Notion of element and periodic properties
Logically, a necessary prerequisite to the construction of the periodic
table was the discovery of a sufficient number of individual elements that make
it possible to find some pattern in chemical behavior and properties. Over the
next two centuries it was acquiring a better understanding of these properties,
as well as discovering many new elements.

5. The word "element" comes from the Greek science, but his modern
notion appeared throughout the seventeenth century, although there is no clear
consensus regarding the process that led to its consolidation and widespread
use. Some authors cite as precedent the phrase of Robert Boyle in his famous
work The skeptical chemist where elements called "certain primitive and simple
bodies are not formed by other bodies, and each other, and which are the
ingredients that make up immediately and are resolved in the end all perfectly
mixed bodies ". Actually, that phrase appears in the context of the critique of
Robert Boyle to the four Aristotelian elements.
Throughout the eighteenth century affinity tables picked up a new way of
understanding the chemical composition, which is clearly stated by Lavoisier in
his Elementary Treatise on Chemistry. This led to distinguish first what the
known substances were hitherto chemicals, what their properties and how to
isolate them.
The discovery of a large number of new elements, and the study of their
properties revealed some similarities between them, increasing the interest of
chemists to seek some kind of classification.
The atomic weights
In the early nineteenth century, John Dalton (1766-1844) developed a
new conception of atomism, which came thanks to his studies weather and
atmospheric gases. His main contribution was to the development of a
"chemical atomism" that allowed integrating the new definition of element by
Antoine Lavoisier (1743-1794) and the laws of chemistry weights (defined
proportions, multiple proportions, proportions reciprocal).
Dalton used the knowledge of proportions in which substances react his
time and made some assumptions about the way losátomos combined thereof.
Established as a reference unit mass of a hydrogen atom (although it suggested
other in those years) and referred the other values to this unit, so you could
build a system of relative atomic masses. For example, in the case of oxygen,
Dalton started from the assumption that water was compuestobinario formed by
a hydrogen atom and one oxygen. I had no way to prove this point, so it had to
accept this possibility as an a priori hypothesis.
Dalton knew that 1 part of hydrogen is combined with 7 parts (8 today
would claim) of oxygen to produce water. Therefore, if the combination
produced atom by atom, ie a hydrogen atom combined with an oxygen atom,
the ratio between the masses of these atoms should be 1:7 (or 1:8 calculated
on the present). The result was the first table of relative atomic mass (or atomic
weights, Dalton called them) which was later modified and developed in

6. subsequent years. Inaccuracies above resulted in a series of controversies and
disparities in formulas and atomic weights, which only begin to improve, but not
entirely, in the Karlsruhe Congress in 1860.
Metals, non-metals, metalloids and transition metals
The first classification of known elements, was proposed by Antoine
Lavoisier, who proposed that the elements are classified into metals, non-
metals and metalloids ometales transition. Although very practical and
functional yet modern periodic table, was rejected because there were many
differences both in the physical and in the chemical.
Triads Döbereiner
One of the first attempts to group items of similar properties and relate
the atomic weights is due to the German chemist Johann Wolfgang Döbereiner
(1780-1849) who in 1817 showed that there was the remarkable resemblance
between the properties of certain groups of three elements, with a gradual
change from first to last. Subsequently (1827) reported the existence of other
groups of three elements that are given the same ratio (chlorine, bromine and
iodine; sulfur, selenium and tellurium, lithium, sodium and potassium).
These groups of three triads and were dubbed by 1850 had already
found about 20, indicating a certain regularity between the chemical elements.
Döbereiner tried to relate the chemical properties of these elements (and
their compounds) with the atomic weights, watching a great analogy between
them, and a gradual change from first to last.
In his classification of triads (three-element array) Döbereiner explained
that the average atomic weight of the weights of the extreme elements, is
similar to the atomic weight of the middle element. For example, for the triad
Chlorine, Bromine, Iodine atomic weights are respectively 36, 80 and 127, if we
add 36 + 127 and divide by two, we get 81, which is about 80 and if we give our
periodic table the element with the atomic weight of approximately 80 is
bromine which causes an apparent ordering match triads

7. Law of octaves of Newlands
In 1864, the English chemist John Alexander Reina Newlands informed
the Royal College of Chemistry (Royal College of Chemistry) his observation
that by ordering the elements in increasing order of their atomic weights (apart
from hydrogen), the eighth element from any another had very similar properties
to the first. At this time, the so-called noble gases had not yet been discovered.
This law showed a certain organization of the elements into families
(groups), with properties very similar to each other and in periods, consisting of
eight elements whose properties were gradually changing.
The name octave is based in Newlands intended to relate these
properties to scale will exists in musical notes, so that he gave his discovery the
name of law of octaves.
As calcium from this rule failed to be met, this arrangement was not
appreciated by the scientific community that despised and ridiculed, until 23
years later was recognized by the Royal Society, which awarded Newlands its
highest award, the Medal Davy.
Mendeleev Periodic Table
In 1869, the Russian Dmitri Ivanovich Mendeleev published his first
periodic table in Germany. A year later he hizoJulius Lothar Meyer, who based
his periodic table in the periodicity of the atomic volumes as a function of the
atomic mass of the elements. By this date were already known elements 63 90
that exist in nature. The classification was carried out by the two chemicals in
accordance with the following criteria:
• They put the elements in order of increasing atomic mass.
• The grouped in rows or periods of different lengths.
• They placed in the same group elements have similar chemical properties,
such as valence.
The first Mendeleev periodic table was not well received at first. After
several changes in 1872 published a new periodic table consists of eight
columns split into two groups each, after the years family called A and B.
In its new slogan table general formulas of the hydrides and oxides of each
group and therefore implicitly lasvalencias of these elements.

8. This table was completed in the late nineteenth century with a larger
group, the zero group, consisting noblesdescubiertos gases during those years
on the air. Russian chemist not accepted in principle such a discovery, since
those elements did not fit on your table. But when, due to its chemical inactivity
(zero valence) were assigned zero group, the Periodic Table was more
complete.
Mendeleev's great merit was to predict the existence of elements. He left
empty boxes to place in them the elements whose discovery would take place
years later. Even predicted the properties of some of them: elgalio (Ga), which
he called eka-aluminum to be located below the aluminum germanium (Ge),
which he called eka-silicon, scandium (Sc), and technetium ( Tc), which
chemically separated from the remains of a synchrotron in 1937, became the
first element in a predominantly produced artificial
Structure and organization of the periodic table
The current periodic table is a system which classifies the elements
known to date. Are placed from left to right and top to bottom in order of
increasing atomic numbers. The items are arranged in seven horizontal rows
called periods, and in 18 vertical columns called groups or families.
Groups
The vertical columns of the periodic table are called groups. There are 18
groups in the standard periodic table, of which ten are short groups and the
remaining eight long, that many of these groups correspond to known families
of chemical elements in the periodic table was devised to sort these families in
a consistent and easy to see.
All items belonging to a group have the mismavalencia atomic, meaning
the number of electrons in the last layer, and therefore have similar properties
to each other.
The modern explanation of the ordering in the periodic table is that the
elements of a group have the same configurations electrónicassimilares and
atomic valence, or number of electrons in the last layer. Since the chemical
properties are deeply dependent interactions of electrons that are located in the
outermost level, the elements of a group have similar chemical properties.
For example, the elements in group 1 have a elecrónica condiguración
ns1 and a valence of 1 (one outer electron) and all tend to lose that electron
when bound as positive ions +1. The elements in the last group on the right are
the noble gases, which have filled their last energy level (octet rule) and,
therefore, are exceptionally unreactive and are also called inert gases.

9. Numbered from left to right using Arabic numerals, as the last
recommendation of the IUPAC (according to the old proposal IUPAC) in 1988
and in parentheses as the U.S. system, nine groups of the periodic table are:
• Group 1 (IA): the alkali metals • Group 2 (IIA): the alkaline earth metals.
• Group 3 (IIIB): the scandium family • Group 4 (IV B): Titanium family
• Group 5 (V B): Vanadium family • Group 6 (VI B): Chrome family
• Group 7 (VII B): Manganese family • Group 8 (VIII B): Iron Family
• Group 9 (IX B) Cobalt family • Group 10 (X B): Nickel family
• Group 11 (I B) Copper Family • Group 12 (II B): Zinc family
• Group 13 (IIIA): the earth • Group 14 (IV A): the carbonoideos
• Group 15 (V A): the nitrogenoideos • Group 16 (VI A): the chalcogens or
chalcogens
• Group 17 (VIIA): the halogens • Group 18 (VIII A): the noble gases
Periods
The horizontal rows of the periodic table are called periods or families.
The number of energy levels an atom has determines the period to which it
belongs. Each level is divided into different subshells, which as atomic number
increases are filled in this order:
Following this rule, each element is positioned according to its electron
configuration and shapes the periodic table. Electrons in the outermost levels
largely determine the chemical properties, so that they tend to be similar within
a group, however atómicavaría mass considerably even between adjacent
elements. On the contrary, of two adjacent same period have a mass similar but
different chemical properties.
The periodic table has 7 periods:
• Period 1
• Period 2
• Period 3
• Period 4
• Period 5

10. • Period 6
• Period 7
Blocks
The periodic table can also be divided into blocks according to the orbital
elements are occupying the outermost electrons, according to the Aufbau
principle.
The blocks or regions are named according to the letter that refers to the
outermost orbital: s, p, d and f. There could be more to fill other orbital
elements, but have not been synthesized or discovered, in this case is
continued to name alphabetical order.
• Block s
• Block p
• Block d
• Block f

11. Acids and Bases
When the solution concentration of hydrogen ions (H +) is greater than
the hydroxyl ion (OH-), is said to be acidic. Instead, calls to the basic or alkaline
solution whose hydrogen ion concentration is less than the hydroxyl ion. A
solution is neutral when the hydrogen ion concentration is equal to the hydroxyl
ion. Pure water is neutral because it [H +] = [OH-].
The first definition of acid and base was coined in the 1880s by Savane
Arrhenius who defined as substances that can donate protons (H +) or
hydroxide ions (OH-), respectively. This definition is of course incomplete
because molecules exist as ammonia (NH3) lacking the OH-group and possess
basic characteristics.
A more general definition was proposed in 1923 by Johannes Bronsted
and Thomas Lowry who enunciated that an acidic substance is one that can
donate H +, exactly equal to the Arrhenius definition, but unlike the latter, they
defined a base as a substance that can accepting protons.
A more general definition of acids and bases was proposed by Gilbert
Lewis who described that an acid is a substance that can accept an electron
pair and a base is one that can donate that pair.
Acids and bases are characterized by:
acids Bases
They taste sour (lemon, vinegar, etc.). Caustic or bitter taste (bleach)
In aqueous solution or tincture reddens
litmus paper turning blue
in the aqueous solution or tincture of
litmus paper
Reddened discolour bases
phenolphthalein
redden the alcoholic solution of
phenolphthalein
Cause effervescence with calcium
carbonate (marble)
produce a feeling greasy to the touch
React with some metals (such as zinc,
iron, ...), evolving hydrogen
by acid substances dissolved
Precipitate
Neutralize the action of bases neutralize the action of acids
In aqueous solution allowed to pass
electrical current, experiencing them
both a chemical decomposition
in aqueous solution allowed to pass
electrical current, experiencing them,
while chemical breakdown
Concentrates destroy living biological
tissues (are corrosive to the skin)
Soft to the touch but corrosive to the
skin (destroy living tissue)
to certain vegetable dyes Dan redden certain blue vegetable
dyes
Dissolve substances dissolve fats and sulfur
Lose their properties to react with bases lose their properties to react with
acids
Are used in the manufacture of soaps
from fats and oils

12. Both acids and bases are found in large quantities in products used in daily life,
industry and hygiene, as well as fruits and other foods, while excess or defect of
their relative amounts in our body results in problems health.
Acid-Base Theory Lowry-Bronsted
According Bronsted Lowry acids are all compounds capable of yielding
ions or protons (H +) in the middle and base are those which can accept
protons from the medium.
When a molecule or anion can take a H + (Bronsted-Lowry base),
forming its "conjugate acid"
Strength of the acids and bases
The strength of an acid or a base is determined by their tendency to lose
or gain protons. The acids can be divided into strong (HCI, SO4H2, HNO3, etc.)
And weak (-PO4H2, CH3COOH, CO3H2, etc.). The first molecules dissociate
into virtually all being dissolved in water. The second only ionize a small
proportion of their molecules. Hence, for the same acid concentration, hydrogen
ion concentration is higher in strong acid solutions in the weak.
The bases can also be divided into strong (NaOH, KOH, Ca (OH) 2, etc.).
And weak (NH3, trimethylamine, aniline, etc.).. The first completely dissociate in
solution. As for weak acids, the dissociation constants of the weak base (KB)
reflect the degree of ionization.
A useful generalization about the relative strengths of the acid-base pairs
is that if an acid is strong, its conjugate base is weak and, for the bases, if a
substance is a strong base, its conjugate acid is weak.

13. Conclusion
The periodic table of chemical elements plays an important role in the
development of science in general and chemistry and physics in particular,
because it lays the foundation for understanding the complex and intricate
relationships between the atoms, the fundamental units which are built all the
objects around us. Moreover, it would be very discouraging to have a science
chemicals that have as an object of study to only one of the elements or
compounds known, or even a group of them.
Although Mendeleev is undeniable contribution to the understanding of
chemistry, we can not forget that his work would not have been possible without
the help of many other scientists, some of them are anonymous, experiments
were patiently, meditated their results and generated theories.
Moreover, the work does not end with Mendeleev's table, as it shapes us
are related knowledge as the properties of the elements, but why. Thus, it is
necessary to find these explanations in the back of the atomic structure in these
objects we can not see but which we know more every day.

14. Bibliography
Raymond Chang, "Quimica" Sexta Edición, McGraw-Hill Pág. 248 – 250.
Microsoft Encarta 2002