Atoms of a kind are called elements, the elements are arranged in the Periodic Table. While the most important tool you’ll need to be successful in this class is, of course, your brain, a very close second would be the periodic table. You’ve no doubt seen it before, many times. It’s on t-shirts, posters, movies, books.
What is useful for? In chemistry, a better question would be what is it NOT useful for? By simply knowing where an element is located on the periodic table, you can know it’s physical properties (is it a solid, liquid, or gas? is it metallic?), how it behaves in a chemical reaction, even how much product you can expect from a chemical reaction, even how it’s electrons are organized around its nucleus.
The Periodic Table may look random, but every single thing about it has meaning and is useful for understanding the elements. Let’s take a quick walk through the table and learn some of its most important parts. You should memorize the facts below.
First, elements to the left of the stairstep line below are metals. That means they are good conductors of heat and electricity, they are malleable (they can be made into a flat sheet, like aluminum foil), they are ductile (they can be drawn into a wire), and they are reflective. The only exception would be hydrogen which falls on the left of that line but it is in fact a non-metal.
Elements to the right of that stairstep line are nonmetals. That means they are poor conductors of heat and electricity, they are not malleable, they are not ductile, and they are not reflective.
Some elements share properties between metals and non-metals. These are called semi-metals or metalloids. The metalloids are boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and polonium (Po).
Vertical columns on the Periodic Table are called groups. Elements within a group have similar reactivities. That alone shows the incredible usefulness of the periodic table. If I were to ask you to name an element that reacts the same way as, say, sodium (Na), you would probably have no idea. But with a periodic table in hand, the answer is as easy as finding which column (group!) Na is found. Any element in that same group will react in similar ways to sodium. You might pick lithium, or potassium, or rubidium, or any other element in group 1.
Groups have specific names. On some periodic tables, you will notice two sets of numbers, one that uses A’s and B’s along with Roman numerals, another that just counts of the groups from 1 to 18. The latter is the more modern convention and it’s what we’ll use in this course.
Horizontal rows on the Periodic Table are called periods. Elements within a period have properties that vary in a predictable way.
All of the elements have both a name and a one or two letter abbreviation. Every abbreviation begins with a capital letter. If the abbreviation has a second letter, it is ALWAYS lowercase. This helps to avoid a lot of confusion! Just think of the difference between the beautiful lustrous transition metal, Cobalt (Co) and the toxic gas that emits from the exhaust pipe of a gasoline burning car, carbon monoxide (CO). Their abbreviations differ only by the capitalization of the letter O.
Finally, you’ll notice that the symbols don’t always seem to align with the element names. For example, B for boron makes sense, but where is the W in Tungsten? How does iron become Fe? The answer is that the periodic table names are all rooted in history. Some of the abbreviations come from Latin (Fe is from ‘ferrum’ which means ‘firm’), some from other languages (K is from the German word Kalium, what we call potassium), and some from their source (W for tungsten is because it comes from the mineral Wolframite, which is also a German word!).