C3: Elements built from
|In the previous section we learned we could make these three building blocks (protons, neutrons, and electrons) out of energy. Now these three will be used to build the elements, or more specifically, the atoms of each element.
Before we get into their building block capabilities, it's useful to know that you already have a personal connection to these particles through your senses.
SIGHT: All light or colors that you see are the result of movement by electrons. When electrons slow down or stop, they give off light including visible light.
TASTE: You taste protons when you sense a food has a tart, sharp, or vinegar taste. Protons are being released by acids in the food.
|WEIGHT: You feel the weight of neutrons because they roughly double the weight of everything you lift.
Every textbook I've seen introduces protons, electrons, and neutrons as the building block of atoms, and they do it in a nonchalant, matter-of-fact manner. They also either mention or imply that all protons, electrons, and neutrons are identical to every other proton, electron, or neutron. That is true, but think how amazing that is. I'll repeat that. Every proton in the universe is exactly like every other proton in the universe. The same is true with electrons and neutrons.
The only thing that I know that also has exact copies are numbers. For example, a "3" used here is exactly the same "3" others may use. We don't have to worry about a count of 3 that I do is different than the count of 3 that you do. So the only explanation I have for protons, electrons, and neutrons having exact copies is that they must be mathematically engineered. In other words, some kind of mathematical formula must be directing their assembly.
We have all heard that everything is unique. Even "identical" twins have differences, but the protons, electrons, and neutrons in these twins could easily be exchanged with ones from the atoms that make up the dirt or grass. Yes, the protons, electrons, and neutrons in the atoms of your body, could be exchanged with any protons, electrons, or neutrons from anything in the universe and you would never know the difference because they are identical. I find that odd and amazing at the same time.
Let's get back to building blocks. What makes good building blocks?
The ever popular Tinkertoys gives us some clues.
Blocks must allow for ways to connect to one part to another.
Tinkertoys had circular wood blocks with eight holes around the perimeter and one through its center. Sticks acted as connectors.
With sticks of different lengths and a few kinds of blocks with holes in them, a wide variety of things could be assembled.
How do the proton, neutron, and electron compare as building blocks?
Electrons by themselves would be poor building blocks because like charges repel, and they would just repel each other.
Protons have the same problem. They repel each other and would build nothing.
But electrons are attracted to protons. Roll cursor over image to see animation.
In the above animation, you see that electrons are attracted to protons, but the electrons don't fall completely into the proton. The electron takes up an orbit around the electron. Part of the reason is that electrons are not just particles, they also behave as a wave. So the wave nature of electrons keeps them from colliding with the proton. To see animation move cursor over the image. The oscillation of the electron creates a spherical electron "cloud." Here, one electron and one proton make up the element, "hydrogen."
Let's say one electron is in orbit around a proton. What would a second electron do? To see animation move cursor over the image. Notice the approaching electron is repelled by the orbiting electron, but at the same time it is attracted to the proton. Its movement is governed by these opposing forces. Also notice that when the second electron joins the first, they stay as far as possible away from each other. (by the way, electrons also spin, and the second electron has to spin [I don't mean orbit] in the opposite direction. Spinning is not shown in this animation)
Here are two hydrogen atoms. Notice that the electron on the left atom is attracted to both it's own proton and to the right proton of the right hydrogen. Likewise, the electron in the right hydrogen is attracted to both protons. So even though protons repel each other, the fact that they pull on electrons in the other atoms, causes them to pull together.
|Two hydrogen atoms will stay together because the electrons have room to stay away from each other as they orbit both hydrogen atoms. So even though there is repulsion between the electrons and between the protons, this arrangement minimizes the repulsions allowing for the opposite charge attractions to keep them together.To see animation move cursor over the image. When two atoms share electrons, we say they are bonded together.
|We see that the proton and electron come together to make an hydrogen atom. We also see that two hydrogen atoms will come together and share electrons. However, one proton has a limited attraction force. Two or more protons together would have a greater attraction force on electrons and give us more building block varieties. This is where the neutron comes in.
|This is the helium atom. It has two protons, two neutrons, and two electrons. Even though we've been saying that like charges repel, protons very close to each other feel a new force called the "Strong Nuclear Force." That force causes protons to attract each other. Being neutral, neutrons normally have no effect on protons, but when they are very close, they attract them strongly with the same "Strong Nuclear Force." In short, neutrons help hold the protons together in the nucleus of the atom.
|To the left are two fluorine atoms. The nucleus of the fluorine atom has nine protons. This is possible because the neutrons help hold them together. The nine protons have a tremendous pull (attraction) to electrons in the vicinity. Fluorine has nine electrons surrounding it. Two orbit close to the nucleus. The outer seven spread out to maximize space between them. However there is still space for one more electron. Notice how the two electrons are being attracted by protons from both atoms. This pulls the atoms together, and because there is room, the atoms bond.
Here the fluorine atoms have pulled together and are sharing one electron each. They are now bonded. This is called a single bond (even though two electrons are involved)
Atoms naturally pull on each other because the protons in them pull on the electrons of the other atoms. However, there has to be room for the electrons to merge and be shared by both atoms, otherwise electron repulsion keeps them apart.
Note: Many atoms have room for eight outer electrons.
|Here is carbon. It has six protons, six neutrons, and six electrons. You can see that there are four outer electrons and spaces for four more electrons. This is similar to Tinkertoys, which had blocks that had eight holes around their perimeter. From this picture you can see that carbon could accommodate four electrons and share four of its electrons. Remember fluorine above? Can carbon connect to fluorine?
Fluorine "wants" one electron to fill up its outer shell of electrons. Carbon will provide that electron as long as fluorine shares one of its electrons with carbon.
You can see how four fluorine atoms can connect to one carbon atom. This is exactly what happens. They come together to form carbon tetrafluoride, which is a gas used in refrigeration systems and also fire extinguishing systems.
More importantly, you see how protons, electrons, and neutrons make elements, which are the building blocks for what we call "compounds." Compounds are two or more different elements bonded together.
|Protons, electrons, and neutrons build elements in a rather straight forward manner. For each additional proton, a new element is created. For each proton, an additional electron is attracted. The number of neutrons also increase but not necessarily one neutron per proton. Below are the first six elements. The orbits aren't shown.
|Below I've added nitrogen and oxygen, which are the 7th and 8th elements. These four are important building blocks for living organisms. Atoms are usually drawn as spheres to help show the space that the electrons occupy. The number next to the element name is how many protons it has.
|Above, we draw electrons as little balls that orbit the nucleus, but that's really underestimating the amazing ability of the electron. See movie below a better understanding of what electrons can do.
In the movie above, you see the normal electrons "orbiting" the nucleus. However, the electron forms an oscillating cloud around the nucleus. The electron can also change shape in order to maximize space between it and other electrons. Electrons are always moving and their exact position is not set but based on probability. In other words, the orbits we've been showing are their most probable position. But there is a chance that electrons can be elsewhere at least for a moment. There's probably several electrons in your body that may be on the moon at this moment. Again, electrons are amazing little "particles."
In the above movie, you see carbon with its six electrons orbiting it. Again, this is a simplistic view of the electrons. First, let's change the inner two electrons to the spherical electron cloud that better represents them. The next two electrons also occupy a spherical shell. The next two electrons, however, form the shape of four lobes with each electron being two lobes. Sometimes when carbon bonds with other atoms, these four outer electrons will blend their shapes to form four equally shaped lobes that project out in four directions. The arrangement of the lobes match a four sided pyramid called a tetrahedron. A tetrahedron allows the electrons maximum separation in 3 dimensions.
|Below are four ways that we've represented a carbon atom. The left one is drawn to show the four available spaces for sharing electrons. The bottom left shows all the electrons orbiting particles and contained in a sphere. The second from the right is the same but without the spherical shell. The far right shows a more accurate shape of the electrons. One electron is in each of the four lobes. However, two electrons can fit in each lobe (if they spin in opposite directions). Therefore, there can be a total of eight electrons in these four lobes (2 per lobe). So this is similar to the left drawing that shows eight electrons would fill the outer shell. The right one also shows the tetrahedron (4 sided pyramid) shape that correctly shows how it will align with other atoms that bond with it.
Even though the building of elements is simply adding one proton, one electron and usually one neutron for each new element, the properties of elements can change dramatically and provide a wide range of building blocks.
|Electrons bend themselves into four different shapes (also called orbitals) shown below. They are classified as s, p, d, and f. The letters were chosen based on the spectrum of light they emitted. For example, the s electrons emitted sharp lines of color. d-shaped electrons emitted diffused lines. The Periodic Table of the Elements, shown below in a simplified manner, organizes elements according to the number and shape of their outer electrons. The first two columns of elements have the spherical s-orbital electrons. Column 1 has one s electron, and column 2 has two s electrons. Columns 3 through 12 have d-orbital electrons where each electron usually has four lobes. On the right, the elements with blue background (columns 13-18) have p-orbital electrons as their outer electrons. The p-shape is two lobes for each electron. The bottom two green rows contain elements that have f-orbital electrons as the outer electrons. One element, "U," is uranium. The four types of electrons give elements different ways of connecting. Even within one type, there are variations because of the number of electrons. For example, the d-orbital can have from 1 to 10 electrons. That changes the way elements combine. In short, protons, neutrons, and electrons have built over a 100 elements that can connect in a variety of ways.
|Not only has protons, electrons, and neutron built a diverse array of elements, each element can can exhibit different properties depending on how the atoms of that element is arranged. Take carbon, for example. Below carbon is using the tetrahedron shape, allowing it to connect to four of its neighboring carbon atoms. This makes for a very strong and rigid arrangement, and accounts for why diamonds are the hardest substance known.
|Below shows carbon arranging itself in six-carbon rings, which form layers. This is not a strong arrangement, but it allows the carbon layers to slide over each other. This is graphite, which is good as a lubricant (for locks) and for pencils, so they can slide easily.
Carbon sometimes stacks itself in a random manner. This is true of soot. The word, amorphous, means it has not regular shape. This arrangement makes it soft and also very black, which is good for making pigments.
|Carbon can sometimes arrange itself into spheres, nicknamed buckyballs. Chemists are still researching the many possible uses of this shape.
|A real exciting field is that of nanotechnology, the technology a building structures at the atom level. Below is a diagram of carbon atoms connecting in six sided rings that are connected to make microscopic tubes. Many exotic properties are possible with carbon in these geometric shapes.
|In summary, protons, electrons, and neutrons gave us a super set of building blocks called elements. The elements now become the building blocks for compounds. Compounds are two or more elements bonded together. The number of compounds are almost infinite and form the incredible diversity in the world around us. But remember, no matter how complex things appear, there is simplicity in the building blocks that made it.
|The next section looks at the compounds that make up everything around us.