Why do differences exist in the reactivities of metals

Note that aluminium can be difficult to place in the correct position in the reactivity series during these experiments. This is because its protective aluminium oxide layer makes it appear to be less reactive than it really is. When this layer is removed, the observations are more reliable. It is useful to place carbon and hydrogen into the reactivity series because these elements can be used to extract metals.

Here is the reactivity series including carbon and hydrogen:. Note that zinc and iron can be displaced from their oxides using carbon but not using hydrogen. However, copper can be extracted using carbon or hydrogen.

The reactivity series In a reactivity series, the most reactive element is placed at the top and the least reactive element at the bottom. Hydrogen is also found in acids , which are molecules containing easily-removed hydrogen atoms, usually connected to oxygen, nitrogen, or a halogen. This is a greatly oversimplified explanation of acid-base chemistry. Hydrogen was discovered by the English chemist Henry Cavendish in ; hydrogen had been observed before, but Cavendish was the first to recognize not only that it was an element, but that it burned to form water, which also provided conclusive proof that water was not itself an element.

The name "hydrogen" was derived by the French chemist Antoine Lavoisier from the Greek words hydro "water" and genes "forming". There are three isotopes of hydrogen. Hydrogen-1, or protium , contains one proton in its nucleus, and is by far the most common form of hydrogen Hydrogen-2, or deuterium , contains one proton and one neutron in its nucleus, and comprises the remaining 0. Hydrogen-3, or tritium , contains one proton and two neutrons, and is only found in trace amounts; it is produced by the interaction of cosmic rays on gases in the upper atmosphere, and in nuclear explosions, but since it has a half life of only Heavy water is water made from two atoms of deuterium and one atom of oxygen.

This form of water is literally heavier than "ordinary" water, since an atom of deuterium is twice as heavy as an atom of "regular" hydrogen.

H 2 O has a molar mass of Ordinary water contains about 1 molecule of D 2 O for every molecules of H 2 O. The electrolysis of water concentrates D 2 O in the solution, since the lighter isotope evaporates from the solution slightly faster. Successive electrolysis experiments allow pure heavy water to be produced, but it takes about , gallons of water to produce 1 gallon of heavy water by this method.

Heavy water is used as a moderator in nuclear reactions: it slows down fast-moving neutrons, allowing them to be captured more easily by other nuclei. The generation of heavy water was important during the research on nuclear fission that went into the Manhattan Project during World War II. For a typical person, a fatal dose would require drinking nothing but heavy water for 10 to 14 days, so it's pretty doubtful that heavy water poisoning will be featured on CSI anytime soon.

Most hydrogen is prepared industrially be reacting coal or hydrocarbons with steam at high temperatures to produce carbon monoxide and hydrogen gas a mixture of carbon monoxide and hydrogen is called synthesis gas , and can be used in manufacturing methanol. On smaller scales it can be produced by the reaction of active metals such as zinc, calcium, etc. Hydrogen gas is combined with nitrogen in the Haber process to synthesize ammonia NH 3 , which is widely used in fertilizers.

It is also used in the manufacture of hydrogenated vegetable oils; in this reaction, hydrogen atoms add to the carbon-carbon double bonds in the vegetable oils double-bonded carbons bond to fewer hydrogen atoms than single-bonded carbons — i.

Another use for hydrogen is in rocket fuels: the Saturn V rockets that launched the Apollo lunar missions used , gallons of kerosene and , gallons of liquid oxygen in its first stage S-IC , , gallons of liquid hydrogen and 83, gallons of liquid oxygen in its second stage S-II , and 69, gallons of liquid hydrogen and 20, gallons of liquid oxygen in its third S-IVB stage; the Space Shuttle main engines use , gallons of liquid hydrogen and , gallons of liquid oxygen.

Hydrogen is lighter than air, and was used in balloons and dirigibles also known as airships or zeppelins. Dirigibles were used in city-to-city air travel in the early s, and in trans-Atlantic crossings in the s and s.

During World War I, German zeppelins were used in bombing runs over England, since they could fly higher than the British planes. On May 6, , the German dirigible Hindenburg caught fire as it came in for a landing at Lakehurst Naval Air Station in New Jersey; 35 people out of the 97 aboard and one person on the ground were killed.

The exact cause of the fire is still the subject of speculation, but the disaster signaled the beginning of the end for airship travel. Modern "blimps" use helium to provide lift, which avoids the problem of hydrogen's flammability.

Molecules which contain hydrogen bonded to nitrogen, oxygen, or fluorine can attract one another through the formation of hydrogen bonds. Hydrogen bonds are a particularly strong form of dipole-dipole forces , which arise because of the unequal sharing of electrons in some covalent bonds. If one atom in a covalent bond is more electronegative than the other, it "pulls" harder on the electrons that the two atoms share, giving the more electronegative atom a partial negative charge, and the less electronegative atom a partial positive charge.

The partially negative atom on one molecule attracts the partially positive atom on a neighboring molecule, causing the two molecules to be more attracted to each other than two nonpolar molecules which have no electronegativity differences between their bonded atoms would be. Molecules that interact by these dipole-dipole forces tend to have higher boiling points than nonpolar molecules, because higher temperatures are necessary to overcome the attractive forces between the molecules and separate the molecules into the gas phase.

In the case of O—H, N—H, and F—H bonds, the electronegativity differences are particularly large because fluorine, oxygen, and nitrogen are the most strongly electronegative elements. The attractive forces between molecules containing these bonds are particularly strong, and are given the name hydrogen bonds. Hydrogen bonds are not as strong as covalent bonds, but they greatly influence the physical properties of many substances.

In particular, hydrogen bonds are responsible for the fact that water is a liquid at temperatures at which molecules of similar molecular mass are gases. For instance, hydrogen sulfide, H 2 S, which weighs Ice floats on liquid water because the hydrogen bonds hold the molecules into a more open, hexagonal array, causing the solid form to be less dense than the liquid form. In living systems, hydrogen bonding plays a crucial role in many biochemical process, from the coiling of proteins into complex three-dimensional forms to the structure of the DNA double helix, in which the two strands of DNA are held together by the hydrogen bonding between their nucleic acids components.

In this technique, a sample is placed in a powerful magnetic field usually produced by a superconducting magnet — see the section on Helium , which causes the hydrogen atoms in the sample to resonate between two different magnetic energy levels; pulsing the sample with a burst of radiofrequency radiation typically between to MHz causes the hydrogen atoms to absorb some of this radiation, producing a readout called an "NMR spectrum" which can be used to deduce a great deal of structural information about organic molecules.

Since almost all organic molecules contain hydrogen atoms, this technique is widely used by organic chemists to probe molecular structure; it can also be used to determine a great deal of information about extremely complex molecules such as proteins and DNA.

The technique is nondestructive, and only requires small amounts of sample. NMR spectroscopy can also be performed with the carbon isotope, and several other isotopes of other elements.

This technology is also used in an important medical imaging technique called Magnetic Resonance Imaging MRI ; the water molecules in different environments in the body respond to very slightly different magnetic field strengths, allowing images of tissues and organs to be obtained. This technique can be used in diagnosing cancers and creating images of tumors and other diseased tissues. MRI is also used to study how the brain works by looking at what areas of the brain "light up" under different stimuli.

The term "nuclear" is avoided in the medical application because of its unpleasant associations, even though the only radiation involved is similar to that of an FM radio transmitter. Lithium is a soft, silvery metal, with a very low density, which reacts vigorously with water, and quickly tarnishes in air.

The name of the element is derived from the Greek word for stone, lithos. It is found in the Earth's crust at a concentration of 20 ppm, making it the 31st most abundant element.

Lithium also presents some exceptions to the "typical" Group 1A behaviors. The lithium ion has a very high charge density because of its small size; thus, many lithium salts have significant covalent-bonding character, instead of being purely ionic. Titanium has a high strength to weight ratio, and has important uses in the aerospace industry.

This can then be reacted with a more reactive metal, such as sodium or magnesium, to produce titanium. Another metal, tungsten, forms a carbide which can actually be of use, as it is extremely hard. Tungsten carbide finds use in drill bits as a result of its hardness. To extract tungsten from its ore without forming the carbide, hydrogen is reacted with tungsten oxide at a high temperature, displacing the metal. Instead, a different method altogether is used.

This method, electrolysis, involves passing an electric current through the molten metal ore. This decomposes the ore, splitting it into its component elements, and allowing the metal to be extracted. There are also some caveats to the reaction statements; for example, aluminium will react slowly with water if the thin aluminium oxide layer that prevents it from reacting is damaged. However, despite this, hopefully it still functions as a well-rounded introduction to the reactivity series and some reactions that can be used to evidence it.

Want to share it elsewhere? The evidence is in every breath of air, but answers are harder to come by. The Metal Reactivity Series. Orientation of Collisions. Activation Energy. Nice post!