CHEMISTRY - PERIODIC TABLE - HALOGENS #3

Halogens on the Right

In the second column from the right side of the periodic table, you will find Group Seventeen (Group XVII). 

This column is the home of theHalogen family of elements. 

Who is in this family? The elements included are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). 

What Makes Them Similar?

When you look at our descriptions of the elements fluorine and chlorine, you will see that they both have seven electrons in their outer shell. That seven-electron trait applies to all of the halogens. They are all just one electron shy of having full shells. Because they are so close to being happy, they have the trait of combining with many different elements. They are very reactive. You will often find them bonding with metals and elements from Group One of the periodic table. The elements in the column on the left each have one electron that they like to donate. 

We've just told you how reactive the halogens are. Not all halogens react with the same intensity or enthusiasm. Fluorine is the most reactive and combines with most elements from around the periodic table. Reactivity decreases as you move down the column. As you learn more about the table, you will find this pattern true for other families. As the atomic number increases, the atoms get bigger. Their chemical properties change just a little bit when compared to the element right above them on the table. 

What is a Halide?

The elements we are talking about in this section are called halogens. When a halogen combines with another element, the resulting compound is called a halide. One of the best examples of a halide is sodium chloride (NaCl). Don't think that the halogens always make ionic compounds and salts. Some halides of the world are a part of molecules with covalent bonds. 

PUZZLE PRACTICE

QUIZ - HALOGENS

CHEMISTRY - END OF MODULE QUZZES

AFTER COMPLETEING THE CHEMISTRY MODULES
Take the QUIZZES until you score 100%.  Turn in results to me.

CHEMISTRY QUIZ

ATOMS QUIZ

PERIODIC TABLE - FAMILIES #2

FAMILIES OF THE PERIODIC TABLE

Families Stick Together We just covered the columns and rows of the periodic table. There are also other, less specific, groups of elements. These groups are all over the table. Scientists group these families of elements by their chemical properties. Each family reacts in a different way with the outside world. Metals behave differently than gases, and there are even different types of metals. Some elements don't react, while others are very reactive, and some are good conductors of electricity. The columns of the periodic table are often used to define families. The noble gases are all located in the far right column of the table. That column is labeled Group Zero. Other families can be made of elements in a series. A good example of a series of elements is the transition metal family. The thing to remember is that a family of elements can be found in several ways. You need to run tests and study the elements to determine their properties. Only after that testing can you determine what family an element belongs in. Examples of Families - Alkali Metals - Alkaline Earth Metals - Transition Metals - Halogen Gases - Noble Gases Examples of Physical Properties - Density - Boiling Point - Melting Point - Conductivity - Heat Capacity Examples of Chemical Properties - Valence - Reactivity - Radioactivity PUZZLE PRACTICE

CHEMISTRY - ELEMENT OF THE DAY - SODIUM

11

Na

Sodium

22.98976928

Atomic Number: 11

Atomic Weight: 22.98976928

Phase at Room Temperature: Solid

Element Classification: Metal

Period Number: 3    Group Number: 1    

Group Name: Alkali Metal

What's in a name? From the English word soda and from the Medieval Latin word sodanum, which means "headache remedy." Sodium's chemical symbol comes from the Latin word for sodium carbonate, natrium.

Say what? Sodium is pronounced as SO-dee-em.

History and Uses:

Although sodium is the sixth most abundant element on earth and comprises about 2.6% of the earth's crust, it is a very reactive element and is never found free in nature. Pure sodium was first isolated by Sir Humphry Davy in 1807 through the electrolysis of caustic soda (NaOH). Since sodium can ignite on contact with water, it must be stored in a moisture free environment.

Sodium is used in the production of titanium, sodamide, sodium cyanide, sodium peroxide, and sodium hydride. Liquid sodium has been used as a coolant for nuclear reactors. Sodium vapor is used in streetlights and produces a brilliant yellow light.

Sodium also forms many useful compounds. Some of the most common are: table salt (NaCl), soda ash (Na₂CO₃), baking soda (NaHCO₃), caustic soda (NaOH), Chile saltpeter (NaNO₃) and borax (Na₂B₄O₇·10H₂O).

CHEMISTRY - ELEMENT OF THE DAY - CHLORINE

17

Cl

Chlorine

35.453

Atomic Number: 17

Atomic Weight: 35.453

Phase at Room Temperature: Gas

Element Classification: Non-metal

Period Number: 3    Group Number: 17    

Group Name: Halogen

What's in a name? From the Greek word for greenish yellow, chloros.

Say what? Chlorine is pronounced as KLOR-een or as KLOR-in.

History and Uses:

Since it combines directly with nearly every element, chlorine is never found free in nature. Chlorine was first produced by Carl Wilhelm Scheele, a Swedish chemist, when he combined the mineral pyrolusite (MnO₂) with hydrochloric acid (HCl) in 1774. Although Scheele thought the gas produced in his experiment contained oxygen, Sir Humphry Davy proved in 1810 that it was actually a distinct element. Today, most chlorine is produced through the electrolysis of aqueous sodium chloride (NaCl).

Chlorine is commonly used as an antiseptic and is used to make drinking water safe and to treat swimming pools. Large amounts of chlorine are used in many industrial processes, such as in the production of paper products, plastics, dyes, textiles, medicines, antiseptics, insecticides, solvents and paints.

Two of the most familiar chlorine compounds are sodium chloride (NaCl) and hydrogen chloride (HCl). Sodium chloride, commonly known as table salt, is used to season food and in some industrial processes. Hydrogen chloride, when mixed with water (H₂O), forms hydrochloric acid, a strong and commercially important acid. Other chlorine compounds include: chloroform (CHCl₃), carbon tetrachloride (CCl₄), potassium chloride (KCl), lithium chloride (LiCl), magnesium chloride (MgCl₂) and chlorine dioxide (ClO₂).

Chlorine is a very dangerous material. Liquid chlorine burns the skin and gaseous chlorine irritates the mucus membranes. Concentrations of the gas as low as 3.5 parts per million can be detected by smell while concentrations of 1000 parts per million can be fatal after a few deep breaths.

PERIODIC TABLE - INTRODUCTION #1

PERIODIC TABLE MODULES This set of modules are on the design & use of the Periodic  Table.  Proceed through each module's readings & watching the video clips for details.  Take notes as needed!!! COMPLETE the "ELEMENT of the DAY" COMPLETE the 5 (FIVE) SUPERHERO ELEMENTAL  TRADING CARDS.

INTRODUCTION TO PERIODIC TABLE CHART

The most important chemistry chart there is, and the cornerstone of science since 1869

• The Periodic Table is a chart which arranges the chemical elements in a useful, logical manner.   
• Elements are listed in order of increasing atomic number, lined up so that elements which exhibit similar properties are arranged in the same row or column as each other. 
• The Periodic Table is one of the most useful tools of chemistry and the other sciences. 

Here are 10 fun and interesting Periodic Table facts:

1. While Dmitri Mendeleev is most often cited as the inventor of the modern periodic table, his table was just the first to gain scientific credibility, and not the first table that organized the elements according to periodic properties.
2. There are 90 elements on the periodic table that occur in nature. All of the other elements are strictly man-made.
3. Technetium was the first element to be made artificially.
4. The International Union of Pure Applied Chemistry, IUPAC, revises the periodic table as new data becomes available. At the time of this writing, the most recent version of the periodic table was approved 19 February 2010.
5. The rows of the periodic table are called periods. An element's period number is the highest unexcited energy level for an electron of that element.
6. Columns of elements help to distinguish groups in the periodic table. Elements within a group share several common properties and often have the same outer electron arrangement.
7. Most of the elements on the periodic table are metals. The alkali metals, alkaline earths, basic metals, transition metals, lanthanides and actinides all are groups of metals.
8. The present periodic table has room for 118 elements. Elements aren't discovered or created in order of atomic number. Scientists are working on creating and verifying element 120, which will change the appearance of the table.
9. Although you might expect atoms of an element to get larger as their atomic number increases, this does not always occur because the size of an atom is determined by the diameter of its electron shell. In fact, element atoms usually decrease in size as you move from left to right across a row or period.
10. The main difference between the modern periodic table and Mendeleev's periodic table is that Mendeleev's table arranged the elements in order of increasing atomic weight while the modern table orders the elements by increasing atomic number.

We sometimes use the terms atom and element to mean the same thing.

As far as we know, there are only so many basic elements. Up to this point in time, we have discovered/created over 120. While there may be more out there to discover, the basic elements remain the same.

Iron (Fe) atoms found on Earth are identical to iron atoms found on meteorites. The iron atoms on Mars that make the soil red are the same too. 

With the tools you learn here, you can explore and understand the Universe. You will never stop discovering new reactions and compounds, but the elements will remain the same. 

The List of Elements

Let’s start with 18 ELEMENTS.   "Why start with 18?"  Because the rules for the first eighteen elements are very straightforward: 

1)       Electrons fit nicely into three shells.

·          Remember that the shells are the places you will find the electrons as they spin around the nucleus. 

2)           These elements make up most of the matter in the Universe.

3)           It's a lot easier to remember facts about 18 elements than over 100 elements.

Who are we kidding? We know you want information on more than eighteen elements. We've added the next 18 elements from the fourth period (row) of the periodic table. You need to remember that this is the first row with transition elements. The transition metals have electron configurations that are a little different from the first 18 elements. Make sure you understand the first 18 before you move on to this set. 

Elements as Building Blocks

As you probably saw, the periodic table is organized like a big grid. The elements are placed in specific locations because of the way they look and act. If you have ever looked at a grid, you know that there are rows (left to right) and columns (up and down). The periodic table has rows and columns, and they each mean something different. 

You've got Your Period/Rows...

REVIEW

Even though they skip some squares in between, all of the rows go left to right. When you look at a periodic table, each of the rows is considered to be a different period (Get it? Like PERIODic table.).

In the periodic table,

·          elements have something in common if they are in the same row.

·          All of the elements in a period have the same number of atomic orbitals.

Every element in the top row (the first period) has one orbital for its electrons.

All of the elements in the second row (the second period) have two orbitals for their electrons.

It goes down the periodic table like that. At this time, the maximum number of electron orbitals or electron shells for any element is seven. 

...and Your Groups

Now you know about periods. The periodic table also has a special name for its columns.

·        When a column goes from top to bottom, it's called a group.

·        The elements in a group have the same number of electrons in their outer orbital.

·        Those outer electrons are also called valence electrons. They are the ones involved in chemical bonds with other elements. 

Every element in the first column (group one) has one electron in its outer shell. Every element in the second column (group two) has two electrons in the outer shell. As you keep counting the columns, you'll know how many electrons are in the outer shell. There are some exceptions to the order when you look at the transition elements, but you get the general idea. Transition elements start to add electrons to the second-to-last shell. 

Two at the Top

Hydrogen (H) and helium (He) are special elements. 

Hydrogen can have the talents and electrons of two groups: one and seven. To scientists, hydrogen is sometimes missing an electron, and sometimes has an extra one. 

Helium is different from all of the other elements. It can only have two electrons in its outer shell. Even though it only has two, it is still grouped with elements that have eight (i.e., noble gases).

The noble gases and helium are all "happy," because their outermost electron shell is full. The elements in the center section are called transition elements. They have special electron rules too. 

·  

PERIODIC TABLE - GETTING TO KNOW THE ELEMENTS

HAPPY HALLOWEEN

CHEMISTRY - DANGER MODULE #11

Dangerous Particles

Radioactivity occurs when an atomic nucleus breaks down into smaller particles. There are three types of particles: alpha, beta, and gamma. Alpha particles are positively charged, beta particles are negatively charged, and gamma particles have no charge. The particles also have increasing levels of energy. Alpha has the lowest energy, beta has a bit more, and then gamma is the fastest and most energetic of all the emission particles. 

The term half-life describes the time it takes for the amount of radioactivity to go down by one-half. Let's say you have some uranium (U) (don't try this at home!) and it's radioactive. When your measurements tell you that the level of radioactivity has gone down by one-half, the amount of time that has passed is the half-life. Every isotope has its own unique half-life. The half-life of uranium-235 is 713,000,000 years. The half-life of uranium-238 is 4,500,000,000 years. That's a long time to wait for the radioactivity to decrease. 

Harnessing the Energy

Nuclear energy is the energy released when the nuclei (nuclei is the plural of nucleus) of atoms split or are fused. You know the nucleus is made up of protons and neutrons. Nuclear forces hold all of the pieces together. Fusion is when two nuclei come together. Fission is when one nucleus is split into two or more parts. Huge amounts of energy are released when either of these reactions occurs. Fusion reactions create much of the energy given off by the Sun. Fission creates the much smaller particles that make up the protons and neutrons that physicists are studying every day. In our nuclear reactors, fission is the main process. In the Sun, fusion is the big process. 

Atoms from the Mirror Universe

Since we're talking a little bit about atomic and nuclear physics, we wanted to tell you about antimatter. It's not just found in television shows. Scientists have proved that it is real. While a regular atom has positive and neutral pieces (protons/neutrons) in the nucleus and negative pieces in orbiting clouds (electrons), antimatter is just the opposite. Antimatter has a nucleus with a negative charge and little positive pieces in the orbits. Those positively charged pieces are called positrons. According to news reports in 2010, scientists at CERN (a particle collider) created antihydrogen atoms. They couldn't really do anything with them, since they lasted for less than a second... but they made them! 

CHEMISTRY - ELEMENT OF THE DAY - SULFUR

16

S

Sulfur

32.065

Atomic Number: 16

Atomic Weight: 32.065

Phase at Room Temperature: Solid

Element Classification: Non-metal

Period Number: 3    Group Number: 16   

Group Name: Chalcogen

What's in a name? From the Sanskrit word sulvere and the Latin word sulphurium.

Say what? Sulfur is pronounced as SUL-fer.

History and Uses:

Sulfur, the tenth most abundant element in the universe, has been known since ancient times. Sometime around 1777, Antoine Lavoisier convinced the rest of the scientific community that sulfur was an element. Sulfur is a component of many common minerals, such as galena (PbS), gypsum (CaSO₄·2(H₂O), pyrite (FeS₂), sphalerite (ZnS or FeS), cinnabar (HgS), stibnite (Sb₂S₃), epsomite (MgSO₄·7(H₂O)), celestite (SrSO₄) and barite (BaSO₄). Nearly 25% of the sulfur produced today is recovered from petroleum refining operations and as a byproduct of extracting other materials from sulfur containing ores. The majority of the sulfur produced today is obtained from underground deposits, usually found in conjunction with salt deposits, with a process known as the Frasch process.

Sulfur is a pale yellow, odorless and brittle material. It displays three allotropic forms: orthorhombic, monoclinic and amorphous. The orthorhombic form is the most stable form of sulfur. Monoclinic sulfur exists between the temperatures of 96°C and 119°C and reverts back to the orthorhombic form when cooled. Amorphous sulfur is formed when molten sulfur is quickly cooled. Amorphous sulfur is soft and elastic and eventually reverts back to the orthorhombic form.

Most of the sulfur that is produced is used in the manufacture of sulfuric acid (H₂SO₄). Large amounts of sulfuric acid, nearly 40 million tons, are used each year to make fertilizers, lead-acid batteries, and in many industrial processes. Smaller amounts of sulfur are used to vulcanize natural rubbers, as an insecticide (the Greek poet Homer mentioned "pest-averting sulphur" nearly 2,800 years ago!), in the manufacture of gunpowder and as a dying agent.

In addition to sulfuric acid, sulfur forms other interesting compounds. Hydrogen sulfide (H₂S) is a gas that smells like rotten eggs. Sulfur dioxide (SO₂), formed by burning sulfur in air, is used as a bleaching agent, solvent, disinfectant and as a refrigerant. When combined with water (H₂O), sulfur dioxide forms sulfurous acid (H₂SO₃), a weak acid that is a major component of acid rain.