Download 25 Elements

25 Elements
By:
Luis Martinez
#1 Hydrogen
• Hydrogen is the lightest element.
• It is by far the most abundant element in the universe and
makes up about 90% of the universe by weight.
• Hydrogen as water (H2O) is absolutely essential to life and it
is present in all organic compounds. Hydrogen is the lightest
gas.
• Hydrogen gas was used in lighter-than-air balloons for
transport but is far too dangerous because of the fire risk
(Hindenburg).
#2 Helium
• Helium is one of the so-called noble gases. Helium gas is an
unreactive, colorless, and odorless monoatomic gas. Helium is
available in pressurized tanks.
• Helium is the second most abundant element in the universe after
hydrogen. α-particles are doubly ionized helium atoms, He2+.
• Helium is used in lighter than air balloons and while heavier
than hydrogen, is far safer since helium does not burn.
Speaking after breathing an atmosphere rich in helium results in
a squeaky voice (don't try it!).
#3 Lithium
• Lithium is a solid only about half as dense as
water and lithium metal is the least dense metal.
A freshly cut chunk of lithium is silvery, but
tarnishes in a minute or so in air to give a grey
surface.
• Its chemistry is dominated by its tendency to lose
an electron to form Li+. It is the first element
within the second period.
• Lithium is mixed (alloyed) with Aluminium and
magnesium for light-weight alloys, and is also used
in batteries, some greases, some glasses, and in
medicine.
#4 Beryllium
•
It is a metal and has a high melting point. At ordinary
temperatures, beryllium resists oxidation in air. Beryllium
compounds are very toxic. Its ability to scratch glass is
probably due to the formation of a thin layer of the oxide.
• Its chemistry is dominated by its tendency to lose an electron
to form Be2+. As this ion is so small it is highly polarizing,
to the extent that its compounds are rather covalent. Its small
size means that its complexes tend to be tetrahedral rather than
octahedral.
#5 Boron
• Oron is a Group 13 element that has properties
which are borderline between metals and nonmetals (semimetallic). It is a semiconductor rather
than a metallic conductor. Chemically it is closer
to silicon than to Aluminium, gallium, indium,
and thallium.
• Crystalline boron is inert chemically and is
resistant to attack by boiling HF or HCl. When
finely divided it is attacked slowly by hot
concentrated nitric acid.
#6 Carbon
• Carbon is a Group 14 element and is distributed very
widely in nature. It is found in abundance in the sun,
stars, comets, and atmospheres of most planets.
• Carbon is found free in nature in three allotropic forms:
amorphous, graphite, and diamond .
• Carbon, as microscopic diamonds, is found in some
meteorites. Natural diamonds are found in ancient
volcanic "pipes" such as found in South Africa.
Diamonds are also recovered from the ocean floor off the
Cape of Good Hope.
#7 Nitrogen
• Nitrogen is a Group 15 element.
• Nitrogen makes up about 78% of the atmosphere by
volume but the atmosphere of Mars contains less than
3% nitrogen.
• The element seemed so inert that Lavoisier named it
azote, meaning "without life". However, its compounds
are vital components of foods, fertilizers, and explosives.
• Nitrogen gas is colorless, odorless, and generally inert.
As a liquid it is also colorless and odorless
#8 Oxygen
• Oxygen is a Group 16 element.
• While about one fifth of the atmosphere is
oxygen gas, the atmosphere of Mars contains
only about 0.15% oxygen.
• Oxygen is the third most abundant element
found in the sun, and it plays a part in the
carbon-nitrogen cycle, one process responsible
for stellar energy production.
• Oxygen in excited states is responsible for the
bright red and yellow-green colors of the
aurora. About two thirds of the human body,
and nine tenths of water, is oxygen.
#9 Fluorine
• Fluorine is a Group 17 element.
• Fluorine is the most electronegative and
reactive of all elements.
• It is a pale yellow, corrosive gas, which
reacts with practically all organic and
inorganic substances. Finely divided metals,
glass, ceramics, carbon, and even water burn
in fluorine with a bright flame.
#10 Neon
• Neon is a very inert element. Neon forms an unstable hydrate. In a
vacuum discharge tube, neon glows reddish orange.
• Of all the rare gases, the discharge of neon is the most intense at
ordinary voltages and currents. It is present in the atmosphere as 1
part in 65000.
• Liquid neon has over 40 times more refrigerating capacity than
liquid helium, and more than 3 times that of liquid
hydrogen.
#11 Sodium
• Sodium is a Group 1 element (or IA in older
labeling styles).
• Group 1 elements are often referred to as the
"alkali metals".
• The chemistry of sodium is dominated by the
+1 ion Na+. Sodium salts impart a
characteristic orange/yellow color to flames
and orange street lighting is orange because
of the presence of sodium in the lamp.
#12 Magnesium
• Magnesium is a grayish-white, fairly
tough metal.
• Magnesium is the eighth most
abundant element in the earth's crust
although not found in it's elemental
form.
• It is a Group 2 element (Group IIA in
older labeling schemes). Group 2
elements are called alkaline earth
metals. Magnesium metal burns with a
very bright light.
#13 Aluminium
• Pure Aluminium is a silvery-white metal with many desirable
characteristics.
• It is light, nontoxic (as the metal), nonmagnetic and non
sparking.
• It is somewhat decorative. It is easily formed, machined, and
cast.
• Pure Aluminium is soft and lacks strength, but alloys with
small amounts of copper, magnesium, silicon, manganese, and
other elements have very useful properties.
#14 Silicon
• Silicon is present in the sun and stars and is a
principal component of a class of meteorites
known as aerolites.
• Silicon makes up 25.7% of the earth's crust by
weight, and is the second most abundant
element, exceeded only by oxygen.
• Silicon is important in plant and animal life.
#15 Phosphorus
• Phosphorus is commonly misspelled "phosphorous".
• It is an essential component of living systems and is
found in nervous tissue, bones and cell protoplasm.
Phosphorus exists in several allotropic forms
including white (or yellow), red, and black (or
violet).
• White phosphorus has two modifications. Ordinary
phosphorus is a waxy white solid. When pure, it is
colorless and transparent. It is insoluble in water,
but soluble in carbon disulphide.
#16 Sulfur
• Sulphur (sulfur) is a pale yellow, odorless, brittle solid, which is insoluble in
water but soluble in carbon disulphide. Sulphur is essential to life. It is a
minor constituent of fats, body fluids, and skeletal minerals.
• The spelling of Sulphur is "sulfur" in the USA while Sulphur is common
elsewhere. IUPAC has does not have jurisdiction over language but has decided
sulfur is preferred.
• Sulphur is found in meteorites, volcanoes, hot springs, and as galena, gypsum,
Epsom salts, and barite. It is recovered commercially from "salt domes" along
the Gulf Coast of the USA.
#17 Chlorine
• Chlorine is a greenish yellow gas which
combines directly with nearly all elements.
Chlorine is a respiratory irritant.
• The gas irritates the mucous membranes and
the liquid burns the skin. As little as 3.5 ppm
can be detected as an odor, and 1000 ppm is
likely to be fatal after a few deep breaths.
It was used as a war gas in 1915
• It is not found in a free state in nature, but is
found commonly as NaCl (solid or seawater).
#18 Argon
• Argon is a colorless and odorless gas present to a
very small extent in the atmosphere.
• Argon is very inert (indeed it is referred to as one
of the noble gases) and is not known to form true
chemical compounds.
• It makes a good atmosphere for working with airsensitive materials since it is heavier than air and
less reactive than N2. Today, the chemical symbol
for argon is Ar but until 1957 its symbol was
simply A.
#19 Potassium
• Potassium is a metal and is the seventh most abundant and
makes up about 1.5 % by weight of the earth's crust.
• Potassium is an essential constituent for plant growth and it
is found in most soils. It is also a vital element in the human
diet.
• Potassium is never found free in nature, but is obtained by
electrolysis of the chloride or hydroxide, much in the same
manner as prepared by Davy.
#20 Calcium
• Calcium as the element is a grey silvery
metal. The metal is rather hard.
• Calcium is an essential constituent of leaves,
bones, teeth, and shells. Calcium is the fifth
most abundant element in the earth's crust and
makes up more than 3% of the crust.
• Calcium does not occur as the metal itself in
nature and instead is found in various
minerals including as limestone, gypsum and
fluorite.
#21 Scandium
• Scandium is a silvery-white metal which
develops a slightly yellowish or pinkish cast
upon exposure to air.
• It is relatively soft, and resembles yttrium
and the rare-earth metals more than it
resembles Aluminium or titanium.
• Scandium reacts rapidly with many acids.
#22 Titanium
• Titanium s a lustrous, white metal when
pure.
• Titanium minerals are quite common
• .The metal has a low density, good strength,
is easily fabricated, and has excellent
corrosion resistance.
• The metal burns in air and is the only
element that burns in nitrogen. It is
marvelous in fireworks.
#23 Vanadium
• Pure vanadium is a greyish silvery metal, and
is soft and ductile.
• It has good corrosion resistance to alkalis,
sulphuric acid, hydrochloric acid, and salt
waters.
• The metal oxidizes readily above 660°C to
form V2O5.
• Industrially, most vanadium produced is used
as an additive to improve steels.
#24 Chromium
• Chromium is steel-gray, lustrous, hard, metallic,
and takes a high polish.
• Its compounds are toxic. It is found as chromite
ore.
• Siberian red lead (crocoite, PrCrO4) is a
chromium ore prized as a red pigment for oil
paints.
• Similarly, traces of chromium incorporated into
the crystal lattice of corundum (crystalline
Aluminium oxide, Al2O3)
#25 Manganese
• Manganese metal is gray-white, resembling iron,
but is harder and very brittle.
• The metal is reactive chemically, and decomposes
cold water slowly.
• Manganese is widely distributed throughout the
animal kingdom.
• It is an important trace element and may be
essential for utilization of vitamin B. Manganese
is present in quantity the floor of oceans. It is an
important component of steel.