The Hydrogen Atom Help

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By — McGraw-Hill Professional
Updated on Apr 25, 2014

Introduction to the Hydrogen Atom

What is hydrogen anyway? We hear so much about this element. It may seem, at times, that it is a part of nearly every compound.

The hydrogen atom is a major player among the elements. It is easily the most abundant element in the universe and makes up about 90% of the universe by weight. Hydrogen is involved in most of the everyday compounds that we know of and is particularly important when bonding with carbon in organic chemistry.

Hydrogen gets its name from the Greek word hudor , which means water and gennan , which means to generate. Since the first chemical formula everyone seems to learn is H 2 O, this is an easy one to remember.

Hydrogen was described in detail by Henry Cavendish in 1766. It is made up of one proton and one electron. With one proton, it has an atomic number of 1 and the honor of being the first element of the Periodic Table. A non-metallic, colorless, tasteless, odorless gas at 298 K, hydrogen is highly flammable in the presence of oxygen.

Hydrogen got a bad reputation when engineers in 1937 used it as the lifting element for the huge airship Hindenberg. Later, research into the Hindenberg’s crash and burn found that hydrogen was not the main culprit, but that static electricity had set fire to the aluminum-rich varnish of the airship’s fabric covering, ignited the hydrogen within and caused the disaster. Modern airships, sometimes called blimps for their oblong shape, use an unreactive gas like helium for lift. Helium is twice as dense as hydrogen, but still lighter than air.

Hydrogen, a chameleon among the elements, changes and reacts with most elements, especially carbon. Early investigators noticed its effects even before Cavendish wrote up the specifics of the element. They figured out that hydrogen and oxygen were separate elements of the compound water. Before this idea became accepted, everyone thought water, so limitless upon the earth, was a single element.

Besides being combined with oxygen in the form of water, hydrogen is also found in mines and oil and gas wells. Stars contain an almost limitless supply of hydrogen. Hydrogen is the most abundant element in the universe, making up over 90% of the visible universe’s mass. Here on Earth, hydrogen is combined with oxygen to form water which covers over 70% of the Earth’s surface. However, in the Earth’s crust, hydrogen makes up only about 0.9% of the composition.

Hydrogen Compounds

Hydrogen changes and reacts with most elements, especially carbon, where it combines and forms starches, hydrocarbons, fats, oils, proteins, and enzymes. We will learn more about the hydrogen and carbon bonds in Chapter 10.

Hydrogen also reacts with nitrogen to form ammonia and the halogens to form acidic hydrogen halides. It combines with sulfur to form the rotten egg smell (hydrogen sulfide, H 2 S), and with oxygen and sulfur to form sulfuric acid (H 2 SO 4 ).

Other uses of hydrogen include the hydrogenation of oils, methanol production, rocket fuel, welding, the production of hydrochloric acid, and the reduction of metallic ores. Hydrogen is also important in cryogenics techniques and in superconductivity experiments since its melting point is only just above absolute zero.

Hydrogen Ion

The hydrogen ion is sometimes just called a “proton” in reactions since it carries a positive charge. In liquid form, the H + ion stays in the hydrated state (bonded with everything it can) such as the hydroxonium ion H 3 O + .

When Dalton was doing experiments to figure out the details of the atomic theory and whether or not one atom of an element had a particular mass, he burned hydrogen gas in oxygen to test his hypothesis. This experiment showed that 1 gram of hydrogen reacts with roughly 8 grams of oxygen. It wasn’t until much later that chemists figured out that hydrogen actually bonded with 2 atoms of oxygen, atomic weight roughly 16 grams, to form the liquid we all know and love, water.

One of hydrogen’s isotopes, tritium ( 3 H), is radioactive. Tritium is produced in nuclear reactors and is used in the production of the hydrogen bomb. It is also used as an additive agent in making shimmering paints and as a tracer isotope.

Practice problems for these concepts can be found at – The Hydrogen Atom Practice Test

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