CHEMISTRY - PERIODIC TABLE - ACTINIDE #10

ACTINIDE

Actinide Series of Metals

There are two rows under the periodic 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 radioactiveand 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, high atomic number elements. 

Meet the Family

The actinide family is comprised of fifteen elements that start with actinium (Ac) at atomic number 89 and finish up with lawrencium (Lr) at number 103.
You have probably heard of plutonium (Pu), since it was used in atomic bombs. Uranium (U) is also well known for its radioactivity. They aren't all used to blow up the world. Some of them help us out every day. You can find americium (Am) is some metal detectors. 

ACTIVITY - PERIODIC TABLE 

CHEMISTRY - PERIODIC TABLE - LANTHANIDE #9

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. They are part of the whole table, but it is easier to print the table when they are on the bottom. One of those rows is called the lanthanide series. 
There are a bunch of names you may hear that describe these 15 elements. Some people say lanthanide, some say rare-earth metals, and some say inner-transition elements. No matter what you choose, everyone will know what you mean if you say lanthanide. 

Meet the Family

The lanthanide family is comprised of fifteen elements starting with lanthanum (La) at atomic number 57 and finishing up with lutetium (Lu) at number 71.
You might find some of these elements in superconductors, glass production, or lasers. 

CHEMISTRY - ELEMENT OF THE DAY - SILICON

14

Si

Silicon

28.0855

Atomic Number: 14

Atomic Weight: 28.0855

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 3    Group Number: 14    

Group Name: none

What's in a name? From the Latin word for flint, silex.

Say what? Silicon is pronounced as SIL-ee-ken.

History and Uses:

Silicon was discovered by Jöns Jacob Berzelius, a Swedish chemist, in 1824 by heating chips of potassium in a silica container and then carefully washing away the residual by-products. Silicon is the seventh most abundant element in the universe and the second most abundant element in the earth's crust. Today, silicon is produced by heating sand (SiO₂) with carbon to temperatures approaching 2200°C.

Two allotropes of silicon exist at room temperature: amorphous and crystalline. Amorphous appears as a brown powder while crystalline silicon has a metallic luster and a grayish color. Single crystals of crystalline silicon can be grown with a process known as the Czochralski process. These crystals, when doped with elements such as boron, gallium, germanium, phosphorus orarsenic, are used in the manufacture of solid-state electronic devices, such as transistors, solar cells, rectifiers and microchips.

Silicon dioxide (SiO₂), silicon's most common compound, is the most abundant compound in the earth's crust. It commonly takes the form of ordinary sand, but also exists as quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon dioxide is extensively used in the manufacture of glass and bricks. Silica gel, a colloidal form of silicon dioxide, easily absorbs moisture and is used as a desiccant.

Silicon forms other useful compounds. Silicon carbide (SiC) is nearly as hard as diamond and is used as an abrasive. Sodium silicate (Na₂SiO₃), also known as water glass, is used in the production of soaps, adhesives and as an egg preservative. Silicon tetrachloride (SiCl₄) is used to create smoke screens. Silicon is also an important ingredient in silicone, a class of material that is used for such things as lubricants, polishing agents, electrical insulators and medical implants.

CHEMISTRY - ELEMENT OF THE DAY - NITROGEN

7

N

Nitrogen

14.0067

Atomic Number: 7

Atomic Weight: 14.0067

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 2    Group Number: 15    
Group Name: Pnictogen

What's in a name? From the Greek words nitron and genes, which together mean "saltpetre forming."

Say what? Nitrogen is pronounced as NYE-treh-gen.

History and Uses:

Nitrogen was discovered by the Scottish physician Daniel Rutherford in 1772. It is the fifth most abundant element in the universe and makes up about 78% of the earth's atmosphere, which contains an estimated 4,000 trillion tons of the gas. Nitrogen is obtained from liquefied air through a process known as fractional distillation.

The largest use of nitrogen is for the production of ammonia (NH₃). Large amounts of nitrogen are combined with hydrogen to produce ammonia in a method known as the Haber process. Large amounts of ammonia are then used to create fertilizers, explosives and, through a process known as the Ostwald process, nitric acid (HNO₃).

Nitrogen gas is largely inert and is used as a protective shield in the semiconductor industry and during certain types of welding and soldering operations. Oil companies use high pressure nitrogen to help force crude oil to the surface. Liquid nitrogen is an inexpensive cryogenic liquid used for refrigeration, preservation of biological samples and for low temperature scientific experimentation. Jefferson Lab's Frostbite Theater features videos of many basic liquid nitrogen experiments, such as this one:

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CHEMISTRY - PERIODIC TABLE - TRANSITION METALS #8

Transitioning

Let's 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. We like introducing students to the first eighteen elements, because they are easier to explain. Transition metals are good examples of advanced shell and orbital ideas. They have a lot of electrons and distribute them in different ways. You will usually find that transition metals are shiny, too. Not all of them, but we are sure you've seen pictures of silver (Ag), gold (Au), and platinum (Pt). 

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 (Sc) 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. You need to remember that those electrons are added to the second-to-last shells. 

The transition metals are able to put up to 32 electrons in their second-to-last shell. Something like gold (Au), with an atomic number of 79, 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. You will find it's usually 2, 8, 18 or 32 for the maximum number of electrons in an orbital. 

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 achemical 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, the electrons want to 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. 

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CHEMISTRY - ELEMENT OF THE DAY - BORON

5

B

Boron

10.811

Atomic Number: 5

Atomic Weight: 10.811

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 2    Group Number: 13    

Group Name: none

What's in a name? From the Arabic word Buraq and the Persian word Burah, which are both words for the material "borax."

Say what? Boron is pronounced as BO-ron.

History and Uses:

Boron was discovered by Joseph-Louis Gay-Lussac and Louis-Jaques Thénard, French chemists, and independently by Sir Humphry Davy, an English chemist, in 1808. They all isolated boron by combining boric acid (H₃BO₃) with potassium. Today, boron is obtained by heating borax (Na₂B₄O₇·10H₂O) with carbon, although other methods are used if high-purity boron is required.

Boron is used in pyrotechnics and flares to produce a green color. Boron has also been used in some rockets as an ignition source. Boron-10, one of the naturally occurring isotopes of boron, is a good absorber of neutrons and is used in the control rods of nuclear reactors, as a radiation shield and as a neutron detector. Boron filaments are used in the aerospace industry because of their high-strength and lightweight.

Boron forms several commercially important compounds. The most important boron compound is sodium borate pentahydrate (Na₂B₄O₇·5H₂O). Large amounts of this compound are used in the manufacture of fiberglass insulation and sodium perborate bleach. The second most important compound is boric acid (H₃BO₃), which is used to manufacture textile fiberglass and is used in cellulose insulation as a flame retardant. Sodium borate decahydrate (Na₂B₄O₇·10H₂O), better known as borax, is the third most important boron compound. Borax is used in laundry products and as a mild antiseptic. Borax is also a key ingredient in a substance known as Oobleck, a strange material 6th grade students experiment with while participating in Jefferson Lab's BEAMS program. Other boron compounds are used to make borosilicate glasses, enamels for covering steel and as a potential medicine for treating arthritis.

CHEMISTRY - PERIODIC TABLE - ALKALINE EARTH METALS #7

ALKALINE METALS

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 reactivefamily of elements in the periodic table. 
Do 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 higher pH levels means that they 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 shell. They are ready to give up those two electrons in electrovalent/ionic bonds. Sometimes you will see them with two halogen atoms, as with beryllium fluoride (BeF₂), and sometimes they might form a double bond, as with calcium oxide (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. While radium is not found around your house anymore, it used to be an ingredient in glow-in-the-dark paints. It was originally mixed with zinc sulfide (ZnS). 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. Magnesium can be found in chlorophyll molecules. 

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CHEMISTRY - ELEMENT OF THE DAY - BERYLLIUM

4

Be

Beryllium

9.012182

Atomic Number: 4

Atomic Weight: 9.012182

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 2    Group Number: 2    

Group Name: Alkaline Earth Metal

What's in a name? From the Greek word beryl, a type of mineral.

Say what? Beryllium is pronounced as beh-RIL-ee-em.

History and Uses:

Although emeralds and beryl were known to ancient civilizations, they were first recognized as the same mineral (Be₃Al₂(SiO₃)₆) by Abbé Haüy in 1798. Later that year, Louis-Nicholas Vauquelin, a French chemist, discovered that an unknown element was present in emeralds and beryl. Attempts to isolate the new element finally succeeded in 1828 when two chemists, Friedrich Wölhler of Germany and A. Bussy of France, independently produced beryllium by reducing beryllium chloride (BeCl₂) with potassium in a platinum crucible. Today, beryllium is primarily obtained from the minerals beryl (Be₃Al₂(SiO₃)₆) and bertrandite (4BeO·2SiO₂·H₂O) through a chemical process or through the electrolysis of a mixture of molten beryllium chloride (BeCl₂) and sodium chloride (NaCl).

Beryllium is relatively transparent to X-rays and is used to make windows for X-ray tubes. When exposed to alpha particles, such as those emitted by radium or polonium, beryllium emits neutrons and is used as a neutron source. Beryllium is also used as a moderator in nuclear reactors.

Beryllium is alloyed with copper (2% beryllium, 98% copper) to form a wear resistant material, known as beryllium bronze, used in gyroscopes and other devices where wear resistance is important. Beryllium is alloyed with nickel (2% beryllium, 98% nickel) to make springs, spot-welding electrodes and non-sparking tools. Other beryllium alloys are used in the windshield, brake disks and other structural components of the space shuttle.

Beryllium oxide (BeO), a compound of beryllium, is used in the nuclear industry and in ceramics.

Beryllium was once known as glucinum, which means sweet, since beryllium and many of its compounds have a sugary taste. Unfortunately for the chemists that discovered this particular property, beryllium and many of its compounds are poisonous and should never be tasted or ingested.

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