If you desire to improve your chemistry grade take the time to master the secrets of the periodic table. The periodic table is one of the greatest scientific discoveries of all time. It is probably second only to the scientific method. So, it is imperative that you master how to use the periodic table.

Secret #1 The Atomic Number

The atomic is the number of protons in the nucleus of an atom. It is the number of protons that determines the element. The atomic number of hydrogen is "1" and hydrogen has only one proton. The elements are arranged in the periodic table according to the atomic number.

Secret #2 The Modern Periodic Law

The periodic law, first presented by Dmitri Mendeleev and then modified by Henry Moseley, states that the physical and chemical properties of the elements are periodic functions of the atomic number. Which means that there is a repeating pattern in the order of the elements.

Secret #3 The Periods and Families

The seven periods (rows) of the periodic table represent the seven energy levels that the electrons occupy. The eight families (columns) represent the orbital positions of the valence electrons of the elements.

Secret #4 Electron Configuration

The periodic table also accounts for the electron configuration of an electron. The first two families represent the "s" orbitals and the next six families represent the "p" orbitals. It is imperative that you take the time to understand how to write an electron configuration especially for valence electrons.

Secret #5 Valence Electrons

Valence electrons are the electrons occupying the highest energy levels. It is important to master this concept because the valence electrons are the electrons involved in bonding. You determine the valence electrons by counting the "s" and "p" electrons in that period. You can determine that fluorine has seven valence electrons by going to the second period and count over seven times.

How many bonds that fluorine will form is determined by whether fluorine will gain or lose electrons.

Secret #6 The Octet Rule

The octet rule states that atoms tend to gain or lose electrons in order to obtain a noble gas configuration. A noble gas configuration is the most stable situation and nature tends toward stability.

Whether the atom will gain or lose electrons depends on which requires the least energy. Since it will be easier to gain one electron than lose seven, fluorine will tend to gain one electron creating an anion.

So, fluorine will tend to form one bond.

Secret #7 The Driving Force

The driving force behind chemical bonding is the tendency of atoms to gain or lose electrons in order to obtain a noble gas configuration. If an atom requires two electrons to obtain a noble gas configuration then it will gain two electrons by sharing electrons (covalent) or by taking electrons (ionic).

Secret #7.5 Exceptions

It is extremely important that you remain flexible when study chemistry or any science because there are almost always exceptions to the rule. Therefore be prepared for complications or exceptions and learn these exceptions. Don't fight it, just do it.

If you truly want a better understanding of chemistry you must learn the secrets of the periodic table and practice these secrets regularly. I invite you learn more about the "16 must know elements" or chemistry success by going to http://yourChemcoach.com

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Binocular Vision: Experiment

(a) Keep both eyes open and hold a pen or pencil upright at arm's length.

(b) Quickly move the pencil to come exactly in line with a more distant vertical object, such as a window frame or lamp-post.

(c) Close and open the left eye.

(d) Close and open the right eye.

(e) Note any change in the apparent position of the pencil and whether it was the closure of the left or right eye which produced it.

(f) Which eye did you use in lining up the two objects?

Discussion

Although both eyes are kept open to line up the pencil and the distant object, only one eye, the dominant eye, is used to determine the alignment. When this eye is closed, the pencil will appear to 'jump' sideways. It is closure of the dominant eye which produces the jump because, according to the eye now remaining open, the pencil and distant object are not in line. If the student is slow to line up the two objects he or she may be aware of a double image of the near object. Nevertheless, the student is still likely to select the image from the dominant eye.

Awarness of Location of Stimuli. Experiment

(a) Place a glass marble on a non-slippery surface, e.g. on the page of an open notebook.

(b) Cross the first and second fingers of one hand and press on the marble with the tips of these fingers.

(c) Close your eyes and roll the marble firmly, forwards and backwards, side to side and then with a circular motion for about 30 seconds.

(d) Notice any unusual impressions you receive from the fingers.

Discussion

1 The subjective impression should be as if there were two marbles with the fingers pressing
between the two.

2 The areas of the finger-tips employed, with the fingers not crossed, would normally be stimulated only by two surfaces separated in space.. The connections that exist between the receptors and the brain are, presumably, the foundation for this interpretation. When the two areas are stimulated simultaneously by the same object in the absence of visual evidence, the brain makes its usual interpretation, giving the sensation of two objects.

The results also show that we normally rely on information from several sources for our
interpretations. If the subject watches the fingers and marble, it is far more difficult to elicit the impression of two objects.

D G Mackean is the author of GCSE Biology, IGCSE Biology, and many other Biology text books. He has a site of Biology Teaching Resources at http://www.biology-resources.com which includes a bank of experiments for teachers, sample PowerPoint presentations, and many biological drawings

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Every woman knows that no wardrobe is complete without the perfect purse. Shopping for a purse can be exhausting. Going from store to store in search of the perfect one to carry your important possessions around can be time consuming and frustrating. From the simple to the outrageous there is a bag out there to please even the pickiest of purse buyers. If you're planning on hitting the stores in search of the the handbag to complete your spring wardrobe here is a look at what's hot this this season.

• Exotic Reptiles: If you're a fan of fashion inspired by snakes and crocodiles you're in luck. This season's exotic reptile skin purses are extremely popular. Ranging from classic snake skins to iridescent crocodile hides you should be able to find a hobo or a clutch in a bold pattern that reflects your love for the wild side.
• Bright and Bold: This spring's collection of purses have been referred to as candy. This sweet title comes from the bold and bright colors that are filling stores everywhere. Gone are the muted colors of winter, replaced by the bright hues that make spring so fun. Pick your spirits up while you brighten up your wardrobe with a flashy orange or multi-colored handbag. The bright colors turn your purse into a terrific arm accessory bring flair to simple outfits.
• Heavy Metal: While fashion as a whole has seemed to make a quick stop in the 70's, purses are taking a that approach to a new level. Rock N' Roll is a great way to describe the latest purses. This seasons handbags are into heavy metal with large gold, silver, and black chains and other loud embellishments. Look for purses made using patent leather and metallic materials.
• Super Sized: Tired of trying to balance between a clutch and bags resembling luggage all the while staying fashionable? This season over sized is in especially when it comes to the hobo. The trend in purses this season make it possible to bring everything you need without carrying a duffel bag on your shoulder or worrying about whether your zipper is going to break under pressure. For an added bonus look for a over sized handbag inspired by 60's and 70's vintage wear.
• Simple Sophistication: While a large majority of the purses out there this season will leave your head spinning there are a few that use simplicity as their claim fame. If sophistication is a must for your purse of choice, then you will definitely be able to find one that fits your requirements. Spring is full of simple yet stylish purses in timeless color combinations like black and white or brown and tan. Details are kept to a minimum and there is a return to feminine chic that hasn't been seen in awhile.

For trendy clothing and accessories including handbags shop at Baby Phat. Baby Phat offers trendy urban style for women of all ages. Shop at Baby Phat.

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Iguanas are very delicate in the way that the iguana temperature in the habitat is of the utmost importance. This is due to the fact that in the wild, iguanas get their vitamins and nutrients from basking in the hot sun and although it looks like they are being lazy and lethargic, they are actually gathering life-sustaining nutrients. It is also true that an iguana can actually see the UV rays that are emitted from the sun, which is something that humans cannot do to demonstrate how imperative sunlight and heat are to the iguana. In order to understand how to properly regulate iguana temperature in the habitat, lets examine the essential needs of the iguana in captivity.

Proper Heat & Light For Captive Iguanas

There are a number of products available to help regulate the iguana temperature rates inside of the habitat but first, lets outline a few of the misconceptions that are common among new iguana owners.

The fish tank lights that are typically a part of the package comes with a fluorescent UVB light that fixes to the top of the tank is far from the adequate lighting for an iguana. These are very weak and do not give the iguana temperature much difference as they are basically cool lights. The type of UVB light that an iguana requires to maintain proper iguana temperature is typically an incandescent light that is round in structure for heat as well as the UVB fluorescent light that will supply adequate lighting for the iguana.

The fish tank lights are not sufficient in creating the kind of atmosphere that an iguana is comfortable in or can thrive in so be sure that you have proper lighting. Again, the iguana temperature is a direct correlation with the health of the iguana and is incredibly important to the well being of the iguana. It should also be said that the fluorescent UVB light should be placed at least 8-14 inches from the area that the iguana spends most of its time in.

Many first time iguana owners also believe that the entire habitat needs to be the same temperature and this is a complete falsehood as iguana temperature varies just as it would in the wild. The iguana is not only in need of a hot spot to gather UV rays that are imitated by the heating lamps; it is also in need of a cool area.

The cool area as well as the nighttime iguana temperature should be around 74-85 degrees Fahrenheit while the basking area for the iguana should always be a balmy 90-94 degrees Fahrenheit.

If you want to learn more about iguana cages please visit our site which is free to the public. You'll find the best tips on everything to do with iguana care

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