Sam Kean

Most mutations involve typos: Something bumps a cell's elbow as it's copying DNA, and the wrong letter appears in a triplet - CAG becomes CCG.

When it comes to the periodic table, the United States really blew its chance to make a name for itself. If you look over a map of all the elements named for cities, states, countries, and continents, it's not surprising that European locales dominate the map.

Despite the disreputable company it keeps, bismuth is harmless. In fact, it's medicinal: Doctors prescribe it to soothe ulcers, and it's the 'bis' in hot-pink Pepto-Bismol. Overall, it seems like the most out-of-place element on the periodic table, a gentleman among scoundrels.

Polonium is, frankly, pretty useless, and no country in the world except Russia bothered to refine it by the late 2000s.

Atoms consist of a positive nucleus and negative electrons flying around outside it. Electrons closest to the nucleus feel a strong negative-on-positive tug, and the bigger atoms get, the bigger the tug. In really big atoms, electrons whip around at speeds close to the speed of light.

Atoms of Element 118 fill an outer shell with electrons, creating a special type of element called a noble gas. Noble gases are natural turning points on the table, ending one row and pointing to the next.

The price of diamonds can vary greatly depending on size, cut, color, and other factors, including whether they have a history. But because of the rarity of blue boron diamonds, they often fetch more money than gems of similar quality.

Boron is carbon's neighbor on the periodic table, which means it can do a passable carbon impression and wriggle its way into the matrix of a diamond. But it has one fewer electron, so it can't quite form the same four perfect bonds.

On a submicro scale, pure diamond is billions of billions of carbon atoms bonded to one another. If you shrunk yourself down and stood inside the diamond, you'd see nothing but carbon in a perfect pattern in every direction.

Every glass thermometer has subtle variations in the size and shape of the bulb at the bottom and the capillary tube inside, as well as variations in the width of gradations on the side. The compounded effect of these uncertainties is that each thermometer reads temperature slightly differently.

Most people who have encountered mercury have done so after breaking a mercury thermometer. And many of us who saw the liquid balls of mercury scatter across a floor or countertop considered the element the most beautiful on the periodic table.

No element gets people telling crazy stories like mercury does. People have told me tales about pharmacists waxing floors with mercury, mothers rubbing it into babies' skin to kill germs, and 10-year-olds coating dimes in it to make them shine, then blithely carrying them around in their pockets.

Whereas recessive traits require two bad copies of a gene to become noticeable, a dominant trait expresses itself no matter what the other copy does. A benign example of dominance: If you inherit one gene for sticky wet earwax and one gene for dry earwax, the sticky earwax gene wins out every time.

America was probably Europe's equal scientifically by the end of World War I and certainly surpassed it after the chaos of World War II.

Before the Human Genome Project, most scientists assumed, based on our complex brains and behaviors, that humans must have around 100,000 genes; some estimates went as high as 150,000.

Geneticists in the early 1900s believed that nature - in an effort to avoid wasting precious space within chromosomes - would pack as many genes into each chromosome as possible.

The grand saga of how humans spread across the globe will need some amendments and annotations - rendezvous here, elopements there, and the commingling of genes most everywhere.

Mutations can arise anywhere in the genome, in gene DNA and noncoding DNA alike. But mutations to genes have bigger consequences: They can disable proteins and kill a creature.

Junk DNA - or, as scientists call it nowadays, noncoding DNA - remains a mystery: No one knows how much of it is essential for life.

Except for certain moments - when cells are dividing, for instance - chromosomes don't form compact, countable bodies inside cells. Instead, they unravel and flop about, which makes counting chromosomes a bit like counting strands of ramen in a bowl.

We know that genes shape human cultures and human societies: The DNA we inherited from our ancestors makes certain foods taste better, affects the way we care for children, influences what colors we find vibrant, and contributes to our love of socializing, among other examples.

It's often meaningless to talk about a genetic trait without also discussing the environment in which that trait appears. Sometimes, genes don't work at all until the environment awakens them.

The mutated Marfan gene creates a defective version of fibrillin, a protein that provides structural support for soft tissues like blood vessels. Marfan victims often die young, in fact, after their aortas grow threadbare and rupture.

The most profound change that genetics brings about might not be scientific at all. It might be mental and even spiritual enrichment: a more expansive sense of who we humans are, existentially, and where we came from, and how we fit with other life on earth.

Even if we never cure a single disease, the Human Genome Project and other ventures will have been worth it.

There are a few elements - especially platinum and palladium - that have the amazing ability to absorb up to 900 times their own volume in hydrogen gas. To get a sense of the scale there, that's roughly equivalent to a 250-pound man swallowing something the size of a dozen African bull elephants and not gaining an inch on his waistline.

Most stars just fuse hydrogen into helium, but larger stars can fuse helium into other elements. Still larger stars, in turn, fuse those elements into slightly bigger ones, and so on.

Over the years, humans have managed to incorporate nearly every element, light and weighty, common and obscure, into our daily lives. And given how small atoms are and how many of them there are all around us, it's almost certain that your body has at least brushed against an atom of every single natural element on the periodic table.

In some sense, what you might have suspected from the first day of high-school chemistry is true: The periodic table is a colossal waste of time. Nine out of every 10 atoms in the universe are hydrogen, the first element and the major constituent of stars. The other 10 percent of all atoms are helium.

Lithium makes a fine battery because it's a scarily reactive metal. Pure lithium ignites on contact if it touches water - a flake of it would sizzle and fry on the water-rich cells of your skin.

Scientists have continued to tinker with different elements and have learned new ways to store and deliver energy.

One theme I ran into over and over while writing about the periodic table was the future of energy and the question of which element or elements will replace carbon as king.

Scientists didn't discover the noble gas helium - the second most common element in the universe - on Earth until 1895. And they thought it existed in minute quantities only, until miners found a huge underground cache in Kansas in 1903.

If you had to sum up chemistry in one sentence, it might be this: Atoms need to have full shells of electrons to feel satisfied, and different elements steal, shed, or borrow different numbers of electrons to achieve a full shell.

The noble gases, which reside on the East Coast of the periodic table, are its aristocrats - detached and aloof, never bothering to interact with the rabble of common elements that make up the vast majority of the world.

Unlike uranium, plutonium was created in an American lab in 1940, but scientists soon realized that it could produce even wilder chain reactions and even bigger explosions. In fact, fearing another country would create it, too, the American government went to great lengths to keep even the existence of plutonium a secret.

Something funny certainly happens when palladium and platinum come into contact with hydrogen gas; it's one of the great mysteries still waiting to be solved on the periodic table. But it's quite a leap from 'something funny' to cold fusion.

The inability to trace DNA to actual diseases has serious consequences. As does the opposite problem - not being able to trace diseases back to DNA.

Among physicists and chemists, cold fusion - nuclear fusion at close to room temperature - enjoys a reputation about on par with creationism.

Some scientists claim - although these claims are contentious - that they can form deadly isomers with simple X-rays and that hafnium can multiply the power of these X-rays to an astounding degree, converting them into gamma rays up to 250 times more potent than the X-rays.

Many different elements can form isomers, but only a few elements on the periodic table, like hafnium, can form isomers that last more than fractions of a second - and might therefore be turned into weapons.

The body tends to treat elements in the same column of the periodic table as equivalents.

If studying the periodic table taught me nothing else, it's that the credulity of human beings for periodic table panaceas is pretty much boundless.

Your body thinks radium is a great thing to pack into bone - where it kills some cells outright and scrambles the DNA of others, causing problems like cancer.

Radium, discovered by Marie and Pierre Curie in 1898, was especially popular: the 'it' element of its day. Radium glows an eerie blue-green in the dark, giving off light for years without any apparent power source. People had never seen anything like it.

Entrepreneurs in the United States and Europe finally figured out how to separate aluminum from minerals cheaply and also how to produce it on an industrial scale.

People adored Element 13's color and luster, which reminded them of the sparkle of gold and silver - a brand-new precious metal. In fact, aluminum became more precious than gold and silver in the 19th century because it was harder to obtain.

Aluminum is the most common metal in the earth's crust, almost twice as abundant as iron. And one common class of aluminum minerals, collectively called alum, has been in use since at least Greek and Roman times.

After about 1940, scientists generally stopped looking for elements in nature. Instead, they had to create them by smashing smaller atoms together.

While our amplified knowledge of genetics - and the increasing precision of the field - does make it tempting to take on celebrity cases, retro-genetics can't always provide clear answers.