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Group 3: A matter of contention

Depending on who you ask, Group 3 (the third vertical column from the left) of the periodic table includes:

• Scandium, Sc
• Yttrium, Y
• Lanthanum, La
• Actinium, Ac

OR

• Scandium, Sc
• Yttrium, Y
• Lanthanum-Lutetium (La-Lu) <--- "lanthanides"
• Actinium-Lawrencium (Ac-Lr)<--- "actinides," radioactive!

OR

• Scandium, Sc
• Yttrium, Y
• Lutetium, Lu
• Lawrencium, Lr

The different classifications arise from the different logical ways of potentially arranging the elements, e.g., the first arrangement includes La and Ac, both of which are the first elements in the two rows of "f-block" elements (but both behave more like d-block metals), etc. We won't go into it anymore than that here...

The Group 3 elements, as well as the vast majority of the lanthanides and actinides (f-block), can be found hanging out together within the Earth's crust. Of the four (or 32, depending on who you're asking) group 3 elements, Yttrium has perhaps the most real world applications. Due to its ability to form compounds thatphosphoresce, it is used in the manufacture of phosphors for electronic device displays.

The mnemonics for the transition elements are more conveniently formed for periods rather than groups, since four-word sentences are a little hard to come by... So... Once we get to group 12, we will have four new mnemonics to learn!

Alkaline Earth Metals

As a continuation of the periodic table series, this post will cover the second group of elements in the periodic table, the alkaline earth metals:

• Beryllium, Be
• Magnesium, Mg
• Calcium, Ca
• Strontium, Sr
• Barium, Ba
• Radium, Ra

These elements are described as "alkaline" earth metals because they form metal oxides with oxygen, which produce "alkaline" AKA basic (pH > 7) solutions when dissolved in water. One similarity among them is that they all have two electrons in their outermost shell of electrons (the ones that typically participate in chemical reactions). Consequently, they tend to ionize to a +2 cation and form salts with halogens and water, e.g., MgCl2, Ca(OH)2, etc.

Two of the alkaline earth metals are present in human bodies. Can you guess which ones?

Definitely NOT radium (it's radioactive!). Definitely not beryllium (toxic...). The two most prevalent group II elements in our bodies are magnesium and calcium. Think bones and ion pumps and enzyme cofactors...

Now, for the mnemonic:

Beryllium Metal Compounds Should Be Respected.

Periodic Table Series - Part I

The next few entries (18 to be exact) will be focused on the different groups in the periodic table, which is divided into groups and periods. Periods are horizontal rows, while groups are vertical columns, which often include elements with similar or at least related chemical properties. These similarities result from a variety of factors.

First, elements in the same group share the same electron configurations in the outermost "shell" or electronic sphere (the place where electrons are likely to be found) of the atoms. This means that the elements have the same number and "type" of the electrons that are most likely to participate in chemical reactions.

The first group (starting on the left and moving right) of the periodic table, Group 1, includes Hydrogen and the alkali metals, which are:

• Lithium, Li

• Sodium, Na

• Potassium, K

• Rubidium, Rb

• Cesium, Cs

• Francium, Fr

Since the elements have clearly not been put into a very concise and well organized table (which has clearly not been named the "periodic table") and it is obviously not at all a simple matter to come by one of these nonexistent tables, you might want to memorize every single element in the periodic table... just for kicks.

So to aid you in this very important endeavor, I have come up with a few mnemonics. In their entirety, these learning devices will form a poem.

Herein Lies New Knowledge--Requisite Chemical Facts...

For some other useful mnemonics, check out the following link!

Cyanide's toxicity

Ever wonder why cyanide is so toxic? It looks pretty similar to a lot of other small anions... it has similar properties to a lot of other small anions... but it's also much more toxic than a lot of them. So what's so special about it?

All living, breathing humans (and other living, breathing prokaryotes) have an electron transport system/chain (ETS/C) in the mitochondiral membrane within their (our) cells. The main roll of this electron transport system is to--as the name implies--shuttle electrons around and in the process, make ATP. In other words, the electron transport system harnesses energy for the cells in our bodies. Without it, we can't really survive. It is part of the Kreb's cycle, which is a series of biochemical processes that break down food and convert it to energy. 

The last step carried out by the ETS involves the transfer of hydrogen from an enzyme called cytochrome oxidase to oxygen, thereby producing water. Cyanide interacts with cytochrome oxidase in such a way to prevent it from functioning normally in this last step of the ETS. As a result, aerobic metabolism slows way down but glycolysis, which produces pyruvate, continues chugging away. So pyruvate builds up in the cells and gets converted to lactic acid, thereby lowering the delicately balanced pH of the cell. Simultaneously, ATP production grinds to a halt. Without energy, our bodies stop working, i.e., we die. 

Chemiluminescence Demos at West Lake Middle School

Artificially Sweet

Did you ever wonder what was actually in those artificial sweetener packets you might add to your coffee? The popular names on the market are Equal, Sweet N' Low and Splenda, although there are now many commercially available varieties.

Essentially, most of them contain some modified form of sugar that is not metabolized in the same way as standard table sugar (sucrose), thereby adding no caloric value to your diet.

Below are the chemical structures of the compounds present in the three artificial sweeteners mentioned above. Equal contains a mixture of aspartame, maltodextrin and dextrose.
Sweet N' Low is composed of saccharin, potassium bitartrate and dextrose.

Finally, Splenda simply contains a chlorinated derivative of sucrose called sucralose, in which three "OH" groups (hydroxyl groups) have been replaced by chlorine.