Helium

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= Helium =
 * 1) The atomic number of helium is 2, meaning each atom of helium has two protons.
 * 2) Helium has the lowest melting point and boiling point of the elements, so it only exists as a gas except under extreme conditions.
 * 3) Helium is the second-lightest element.
 * 4) Helium is the second-most abundant element in the universe, though it is much less common on Earth.
 * 5) Helium is colorless, odorless, tasteless, non-toxic, and inert.
 * 6) Most helium is obtained by extracting it from natural gas.
 * 7) Helium is the second-least reactive noble gas (after neon).
 * 8) Helium is monatomic under standard conditions.
 * 9) Inhaling helium temporarily changes the sound of a person's voice. Though helium is non-toxic, breathing it can result in asphyxiation due to oxygen deprivation, and can cause damage to the vocal chords if it is used to excess.
 * 10) Evidence of helium's existence came from observation of a yellow spectral line from the sun.
 * 11) is used to displace fuel and oxidizers in storage tanks to make rocket fuel.

Properties:
Helium is a very light, inert, colorless gas. Helium has the lowest melting point of any element. It is the only liquid that cannot be solidified by lowering the temperature. It remains liquid down to absolute zero at ordinary pressures, but can be solidified by increasing the pressure. The specific heat of helium gas is unusually high. The density of helium vapor at the normal boiling point is also very high, with the vapor expanding greatly when heated to room temperature. Although helium normally has a valence of zero, it has a weak tendency to combine with certain other elements. While helium is usually not known to be toxic, it can be harmful. Helium deprives the lungs of oxygen and some have died in the past from not using helium in the right way. However cases like this are very rare and if one is inhaling helium from a balloon at a party, usually the worst thing that will happen will be that the person will pass out.

**Uses:**
Helium is widely used in cryogenic research because its boiling point is near absolute zero. It is used in the study of superconductivity, as an inert gas shield for arc welding, as a protective gas in growing silicon and germanium crystals and producing titanium and zirconium, for pressuring liquid fuel rockets, for use in magnetic resonance imaging (MRI), as a cooling medium for nuclear reactors, and as a gas for supersonic wind tunnels. A mixture of helium and oxygen is used as an artificial atmosphere for divers and others working under pressure. Helium is used for filling balloons and blimps. Doctors today currently use a mixture of helium and oxygen to assist patients with certain respiratory issues.

**Sources:**
Except for hydrogen, helium is the most abundant element in the universe. It is an important component in the proton-proton reaction and the carbon cycle, which account for the energy of the sun and stars. Helium is extracted from natural gas. In fact, all natural gas contains at least trace quantities of helium. The fusion of hydrogen into helium is the sources of a hydrogen bomb's energy. Helium is a disintegration product of radioactive substances, so it is found in ores of uranium, radium, and other elements.

**Basic Facts:**
Helium is a colorless, odorless, tasteless, non-toxic chemical and happens to be the 2nd lightest element on the table of elements. This is why it is commonly used to make balloons float. Another interesting fact about Helium is once helium is free in the air it will actually raise and leave our atmosphere. Even though it can leave and just be gone it is still in abundance. Helium is the chemical element with atomic number and an atomic weight of 4.002602, which is represented by the symbol. It is a colorless, odorless, tasteless, non-toxic, inert monotomic gas heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.Helium is the second lightest element and is the second most abundant element in the observable universe, being present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this figure in our own Sun and in Jupiter. This is due to the very high binding energy (per nucleon ) of helium-4 with respect to the next three elements after helium. This helium-4 binding energy also accounts for its commonality as a product in both nuclear fusion and radioactive decay. Most helium in the universe is helium-4, and is believed to have been formed during the Big Bang. Some new helium is being created currently as a result of the nuclear fusion of hydrogen in stars.


 * Element Classification:** Noble Gas or Inert Gas
 * Usual Phase:** gas
 * Density (g/cc):** 0.1786 g/L (0 °C, 101.325 kPa)
 * Liquid Density (g/cc):** 0.125 g/mL (at its boiling point)
 * Melting Point (°K):** 0.95
 * Boiling Point (°K):** 4.216
 * Critical Point:** 5.19 K, 0.227 MPa
 * Atomic Volume (cc/mol):** 31.8
 * Ionic Radius:** 93
 * Specific Heat (@20°C J/g mol):** 5.188
 * Heat of Fusion:** 0.0138 kJ/mol
 * Evaporation Heat (kJ/mol):** 0.08
 * First Ionizing Energy (kJ/mol):** 2361.3
 * Lattice Structure:** Hexagonal
 * Lattice Constant (Å):** 3.570
 * Lattice C/A Ratio:** 1.633
 * Crystal Structure:** close-packed hexagonal
 * Magnetic Ordering:** diamagnetic
 * CAS registry number:** 7440-59-7
 * Helium Discovery:** Janssen, 1868, some sources say Sir William Ramsey, Nils Langet, P.T. Cleve 1895
 * Helium Electron Configuration:** 1s2
 * Word Origin:** Greek: helios, sun. Helium was first detected as a new spectral line during a solar eclipse.
 * Isotopes:** 7 isotopes of helium are known.

**Interesting Facts**
Helium is often mixed with oxygen for deep sea diving to help reduce the effects of narcosis.
 * -discovered by Sir William Ramsay in London
 * -it was thought to be a medal
 * -independently by P.T. Cleve and N.A. Langlet of Sweden in 1895
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-called the "Noble Gas"
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-one quarter of the universe is made up of helium atoms
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-helium is used to treat asthma
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-it is formed underground
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-most abundant element
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-reserves have been built up for billions of years
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-Helium is non-flammable
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">Much of the world supply of helium is in Texas. However, some is found in Canada. It could run out in around 20 years and then new supplies may have to be found.
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-it has a bright yellow spectrum
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-it never freezes
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-it is lighter than air
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-lowest melting point of the elements
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-helium doesn't burn
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-non-toxic
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-no helium exists in the human body
 * <span style="background-color: #ffffff; color: #333333; display: block; font-family: Arial,Helvetica,sans-serif; font-size: 14px; text-align: left;">-the atomosphere contains around 5 parts per million-
 * <span style="color: #333333; font-family: Arial,Helvetica,sans-serif; font-size: 14px; line-height: 21px;">-Russia could be the biggest source for Helium in the future

One of the many benefits of helium: [].
 * <span style="color: #333333; font-family: Arial,Helvetica,sans-serif; font-size: 14px; line-height: 21px;">-Since helium does not freeze at temperatures below -479 F, there is no current substitute for these very cold applications.

No one will disagree that helium changes your voice, but not everyone believes it is helium that causes your voice to become high-pitched. What it does is change the timbre of your voice. This has nothing to do with falling trees. Timbre is what allows you to tell the difference between the same note played at the same volume on two different instruments. It also helps you hear the different parts of speech, like vowel sounds. Read more: [|How Helium Works | Squeaky Voice | Effects & Dangers of Inhaling] [|http://www.kidzworld.com/article/505-did-donald-duck-inhale-helium#ixzz1uDMh0A2n]
 * Changing your voice:**

Helium is much lighter than air. Because of this, the speed of sound is much higher in helium. When you inhale helium you increase the speed of the sound of your voice. The __shape__ of your vocal tract doesn't change. If you increase the speed of a sound you also increase the wavelength. However, on the way to the ear the sound travels thru air again and the wavelength goes back to normal. It's not the change in __frequency__ that gives you the squeaky voice but a change in pitch. The sound has the same frequencies but helium causes a shift in your timbre. This means the higher frequencies are getting a higher enhancement than normal so the pitch changes. The end result? You sound like a chipmunk.

Read more: [|How Helium Works | Squeaky Voice | Effects & Dangers of Inhaling] [|http://www.kidzworld.com/article/505-did-donald-duck-inhale-helium#ixzz1uDN4JEFh]


 * Symbol:** He **Atomic Number:** 2 **Atomic Mass:** 4.002602 amu **Melting Point:** -272.0 °C (1.15 K, -457.6 °F) **Boiling Point:** -268.6 °C (4.549994 K, -451.48 °F) **Number of Protons/Electrons:** 2 **Number of Neutrons:** 2 **Classification:** Noble Gas **Crystal Structure:** Hexagonal **Density @ 293 K:** 0.1785 g/cm3 **Color:** colorless

Atomic Structure

 * [[image:http://0.tqn.com/d/chemistry/1/0/q/c/1/Helium_Tile.png width="400" height="400"]] ||  || **Number of Energy Levels:** 1
 * First Energy Level:** ||

Isotopes
There are eight known isotopes of helium, but only helium-3 and helium-4 are stable. In the Earth's atmosphere, there is one 3He atom for every million 4He atoms Unlike most elements, helium's isotopic abundance varies greatly by origin, due to the different formation processes. The most common isotope, helium-4, is produced on Earth by alpha decay of heavier radioactive elements; the alpha particles that emerge are fully ionized helium-4 nuclei. Helium-4 is an unusually stable nucleus because its nucleons are arranged into complete shells. It was also formed in enormous quantities during Big Bang nucleosynthesis
 * ** Isotope ** || ** Half Life ** ||
 * He-3 || Stable ||
 * He-4 || Stable ||

Facts

 * Date of Discovery:** 1895
 * Discoverer:** Sir William Ramsay\
 * Name Origin:** From the Greek word //hêlios// (sun)
 * Uses:** balloons, deep sea diving
 * Obtained From:** natural gas deposit, air


 * Classification: || Helium is a noble gas and a nonmetal ||
 * Color: || colorless ||
 * Atomic weight: || 4.00260 ||
 * State: || gas ||
 * Melting point: || -272.2 oC, 0.95 K ||
 * Note: At normal atmospheric pressure, helium does not solidify and so has no melting point. The melting point quoted above is under a pressure of 25 atmospheres. ||
 * Boiling point: || -268.9 oC, 4.2 K ||
 * Shells: || 2 ||
 * Electron configuration: || 1s2 ||
 * Density @ 20oC: || 0.0001787 g/cm3 ||
 * Atomic volume: || 27.2 cm3/mol ||
 * Structure: || usually hexagonal close-packed ||
 * || (v.high pressure needed to solidify helium) ||