Actinide

ACTINIDE SERIES OF METALS

There are two rows under the table. The Lanthanide and Actinide series. The Lanthanide series can be found naturally on Earth. Only one element in the series is radioactive. The Actinide series is much different. They are all radioactive and some are not found in nature. Some of the elements with higher atomic numbers have only been made in labs. There are special laboratories across the world that specialize in experimenting on elements. Some of these particle accelerators have pounded atomic particles into elements with lower atomic numbers. The buildup of additional parts creates short-lived elements.

MEET THE FAMILY

Fifteen elements that start with actinium (Ac) at atomic number 89 and finishing up with lawrencium (Lr) at number 103. It's doubtful your teachers will ever ask you to remember all of the elements in the series, just remember actinium.

Lanthanide

LANTHANIDE SERIES OF METALS

When you look at the periodic table you will see two rows that kind of sit off to the bottom. One of those rows is called the Lanthanide series. There are a bunch of names that you may hear that describe these 15 elements. Some say Lanthanide, some say rare-earth and some say inner-transition elements. No matter what you choose everyone will know what you mean if you say Lanthanide.

MEET THE FAMILY

Fifteen elements that start with lanthanum (La) at atomic number 57 and finishing up with lutetium (Lu) at number 71. It's doubtful your teachers will ever ask you to remember all of the elements in the series, just remember lanthanum.

Transition Metals

TRANSITIONING

Lets start off by telling you that there are a lot of elements that are considered transition metals. Which metals are the transition metals? 21 (Scandium) through 29 (Copper)39 (Yttrium) through 47 (Silver)57 (Lanthanum) through 79 (Gold)89 (Actinium) and all higher numbers.

WHAT MAKES THEM SO SPECIAL?

It all has to do with their shells/orbitals. In CHEM4KIDS we try to stick to the first 18 elements because they are easy to explain. Transition metals are good examples of advanced shell ideas. They have a lot of electrons and distribute them in different ways.

Transition metals are able to put more than eight electrons in the shell that is one in from the outermost shell. Think about argon (Ar). It has 18 electrons set up in a 2-8-8 order. Scandium is only 3 spots away with 21 electrons, but it has a configuration of 2-8-9-2. Wow! This is where it starts. This is the point in the periodic table where you can place more than 8 electrons in a shell.

The transition metals are able to put up to 32 electrons in their second to last shell. Something like gold (Au) has an organization of 2-8-18-32-18-1. Of course, there are still some rules. No shell can have more than 32 electrons. It's usually 18 or 32 for the maximum number of electrons.

ONE MORE THING

Most elements can only use electrons from their outer orbital to bond with other elements. Transition metals can use the two outermost shells/orbitals to bond with other elements. It's a chemical trait that allows them to bond with many elements in a variety of shapes. Why can they do that?

As you learn more, you will discover that most transition elements actually have two shells that are not happy. Whenever you have a shell that is not happy, its electrons can bond with other elements. Example: Molybdenum (Mo) with 42 electrons. The configuration is 2-8-18-13-1. The shells with 13 and 1 are not happy. Those two orbitals can use the electrons to bond with other atoms.

Alkaline Earth

HEADING TO GROUP TWO

So we just covered the alkali metals in Group I. You will find the alkaline earth metals right next door in Group II. This is the second most reactive family of elements in the periodic table. Did you know why they are called alkaline? When these compounds are mixed in solutions, they are likely to form solutions with a pH greater than 7. Those pH levels are defined as 'basic' or 'alkaline' solutions.


A FAMILY PORTRAIT

Who's in the family? The members of the alkaline earth metals include: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). As with all families, these elements share traits. While not as reactive as the alkali metals, this family knows how to make bonds very easily. Each of them has two electrons in their outer shells. They are ready to give up those two electrons in electrovalent bonds. Sometimes you will see them with two halogen atoms (BeF2) and sometimes they might form a double bond (CaO). It's all about giving up those electrons to have a full outer shell.

As you get to the bottom of the list, you will find the radioactive radium (Ra). While radium is not found around your house anymore, it used to be used in glow-in-the-dark paints. The other elements are found in many items including fireworks, batteries, flashbulbs, and special alloys. The lighter alkaline earth metals such as magnesium and calcium are very important in animal and plant physiology. You all know that calcium helps build your bones.