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.