Bonds: Hydrogen

The simplest atom is hydrogen consisting of a nucleus with a single proton and a single electron. The most common atom, that is element  in the known universe is hydrogen. Stars, such as the Sun are formed when huge clouds of hydrogen gas in space collapse under the influence of gravity. When the center of such a collapsing cloud becomes dense enough and hot enough nuclear fusion, the same process which powers the hydrogen bomb, occurs forming a star.

Unlike helium discussed in an earlier post hydrogen does not like to live in isolation. The single electron in a hydrogen atom occupies an unfilled electron shell. If importance is that hydrogen is the only atom to which quantum mechanics equations can be applied and solved exactly. This is fortunate because the functions that result from those equations, hydrogenic orbitals are used to calculate approximate solutions to quantum mechanics equations applied to more complex atoms and molecules.

Hydrogen's unfilled shell wants a second electron. However if a second electron is just added the atom has an overall negative(-1) charge which is not especially stable. Ideally and atom wants to fill its electron shells without giving the stuff made up of that matter an overall positive or negative charge. A way for hydrogen to accomplish this is to partner with another hydrogen and share a pair of electrons.

When this happens the two electrons spend more time on average between the nuclei. Because there is more negative charge on average between the nuclei than elsewhere the positive charged nuclei are pulled together by this "cloud" of negative charge. This is how bonds are formed.  Two atoms that form a bond form a molecule.

Atoms: Helium

Chemists rarely work with isolated atoms because most atoms want to combine with other atoms via the "glue", bonds that hold them together. One atom that does love existing in isolation is helium. Helium is used in applications as trivial as party balloons, in critical industrial welding and in crucial medical equipment such as the MRI.

The name helium derives from the name of the Greek Sun god  Helios. Helium was discovered in the Sun before it was discovered on earth by studying the visible spectrum of sunlight.

The most common helium nucleus contains two protons and two neutrons. When electronically neutralized by a swarm of two electrons Helium assumes its most energetically stable state. That is also its lowest energy state.  In order for an atom to combine with, to react with another atom it must be willing to give up, share or take on an electron. This is simply not the case for helium.

Helium's two electrons  occupy an imaginary spherical layer of charge called an electron shell. For helium this "shell" can contain two electrons. If one could force the lowest energy form of  helium to take on an electron it would occupy the next bigger in radius or higher energy shell becoming a negative charged atom known as an anion.

Helium can be converted to a positive charged cation by removing an electron. One way to do that is to subject helium to a very strong positive electric field which pulls the electron away. This is not a happy situation for a helium atom which will snatch the electron from the first atom it encounters to return to zero charge.

Helium is the lowest atomic number atom among nobel gases which include neon, argon, krypton, xenon and radon. The nobility of these atoms derives from their preference for not reacting with other atoms. The uncharged form of these atoms have closed outer electron shells. All the electron shells inside of the outer electron shell are also filled. This is the most stable form the atom can achieve. Atoms are most energy stable when all their electron shells are filled to capacity.

Helium gas is a declining limited resource that is a byproduct of  natural gas production. Terrestrial helium is produced from radioactive decay which produces alpha particles which are identical to helium nuclei. When these nuclei grab a couple of electrons helium atoms result.

With two protons and two neutrons helium is not the simplest atom. That's hydrogen. You might wonder why not start with the simplest atom. My goal here was to start with an atom that exists in isolation.

Atoms and bonds are the stuff and the glue of all chemistry. Believe it or not it's just that simple in principle.

How to use the stuff and the glue or how we've come to understand how the stuff and the glue work together to give nature its richness in chemistry is why there are millions of pages filled with billions of words in chemical journals. The name of the blog reflects the fact that everyday substances fuel, glass and plastic , fabrics, metals, the air ,  water and food your life depends on are all chemical substances composed of atoms and bonds.

The stuff of chemistry are atoms. Atoms are composed of extremely tiny particles; protons, neutrons and electrons. Protons and neutrons have about the same mass(weight) and are about 1800 times heavier than electrons.

Protons and electrons are electrically charged, protons being arbitrarily assigned positive(+1) and electrons the equal and opposite (-1) charge.

Protons and uncharged neutrons reside in the nucleus which chemists treat as a single heavy positively charged particle. The number of protons Z determines the nuclear charge and is called the atomic number.We chemists leave it to physicists to study the internal structure of the nucleus.

Everyday matter wants to have an overall zero electric charge which is accomplished by matching the sum total of nuclear charges with an equal number of electrons. The much lighter electrons swarm in a cloud of charge around the nucleus in numbers that match the charge of the nucleus. The swarming is because opposite charges attract but also because the physical laws, quantum mechanics, that govern subatomic particles, do not allow the electrons to fall into the nucleus.

Introducing Atoms and Bonds

When you hear the word chemicals in popular culture or in a news story are the first things that come to mind negative such as toxic, pollution, carcinogen, or harmful? What if I put the word natural in front of the word chemical as in all natural chemicals? Does that suddenly change your mindset to think of safe. Can an all natural chemical containing product be less safe than an unnatural product?

For some time I've thought about putting down my thoughts when I hear the way chemicals are talked bout in popular and news media. I was a research chemist for about 20 years. My area of interest was molecular structure analysis. That is I was interested in how atoms and connect together to determine the shapes and sizes of different molecules.

Chemistry is a fascinating, but at times misunderstood, area of science. I want to help anyone who stumbles upon this personal journal better understand this important field. If you were turned off by the way chemistry was taught in your high school or college classes give me another chance to introduce you. For one there will be no tests. Homework is up to you.  My goal is to enlighten readers while improving my writing skills.