Current Event Week 4

Covalent Bonds vs Ionic Bonds

    

There are two atomic bonds- ionic bonds and covalent bonds. They are different in two ways- their structure and their chemical properties. Covalent bonds are made up of two pairs of electrons shared by two atoms. The formation of the covalent bonds of electrons all depends on their electro negativity. (The power of the atom inside a molecule that attracts electrons) A covalent bond is made when two atoms are able to share their electrons, while the ionic bond is formed when the sharing is so unequal that the electrons that are exchanged between the two elements are completely lost, which then becomes a pair of ions. Each atom is made up of protons, neutrons and electrons. At the very center of an atom, which is its nucleolus protons and neutrons are bonded together. The electrons are not in the center but they border around it. Each of the orbits can have a certain number of electrons to be stable. One type of chemical bonding in covalent bonding. That is where two non metallic atoms which are characterized by sharing one pair or more of electrons between atoms and other covalent bonds. The other type of chemical bonds is ionic bonds. They are formed when the electric attractions between appositively charged ions inside a chemical compound. Those kind of bonds occur mainly between metallic and non metallic atoms. There are many differences between ionic and covalent bonds. Here are some of the main ones.

1.        Covalent bonds have a definite shape and low melting/boiling points.—Ionic bonds normally form crystalline atoms and have high melting/boiling points.
2.       Ionic bonds conduct electricity and heat which the covalent bonds can be broken down into their primary structure. 
3.       If you want to break ionic bonds it uses a lot of energy. A lot more than it takes to break covalent bonds.

Those are the main differences between the two bonds.
http://www.diffen.com/difference/Covalent_Bonds_vs_Ionic_Bonds

 

Current Events: 2&3 (Week 2& Week 3)

 

Since for the last two weeks I forgot to complete my current events I decided to make this blog post 2 in 1. I have decided to write about the two of my favorite elements from the periodic table. Gold and Selenium. I really do not know why I like selenium but I guess I just love the sound of it. I really like gold because it is shinny and I love shinny! Anyway the first element, gold will be like the first current event and the second element selenium will be the second blog post! 

Gold:

On the periodic table of elements gold is represented by the symbol 'Au'.  'Au' is a symbol from a Latin word, aurum. Ancient Greeks fell in love with its yellowness and named it after aurum which means ‘light of dawn’. Gold’s atomic number is 79 and its atomic mass is 196. Because the atomic number is 79 it means that it has 79 protons and electrons. Then we subtract the atomic number from the atomic mass to get the number of neutrons, 117. Gold is part of group 7 on the periodic table along with, cooper, silver and uninunium. Gold has a very high melting point, which is 1064 degrees C. Gold is a very dense and heavy element. There are 21 isotopes of gold. On the periodic table we refer to gold as AU-197, which is a stable element. Gold is usually found in free form but can also be found as a compound form with silver, quartz, lead, tellurium, copper, zinc and calcite. Gold can also be found in sea water. ‘Rescuing’ gold from sea is not yet ‘approved’ because of such high cost and scientists are worried that it would not be worth it. Gold is considered to be one of the most valuable elements on earth. Most man and women on this earth crave gold. People wish to own it in any state. Liquid or solid gold has many admirers all around the world. People throughout many civilizations have wanted gold but couldn’t have it. Gold is bendable and able to attract heat. It can be shaped any way we want, stretched to make a thin wire or even pulled together. Gold can be stretched apart to create sheets that are thinner than human hair. Its thickness could be as small as 0.000127 millimeters. But we mostly use it to make jewelry. Gold is a pure form, which means that it is soft. It can only be hardened if you add other metals to it. When you add other metals, only then can it be created into jewelry. Gold is such a boring but interesting element all at once. It is not very rare but many people dream of having gold. I myself, do not own gold but dream about having some. 

Selenium:

 

Selenium is my second favorite element on the periodic table of elements. Again I do not know why, but I really love the name. On the periodic table Selenium is represented as SE. Its atomic number is 34 and the atomic mass is 78. 34 is not only the atomic number but also the number of protons and electrons. Then we take the atomic number and subtract it from the atomic mass to get the number of neutrons which is, 45. (also my favorite number) Selenium’s boiling point is at 220.5 degrees C. which is not as high as gold but still too hot for us. Selenium is a Greek word for moon. Why? We don’t know. Selenium is part of group 16 on the periodic table along with oxygen, sulphur, tellurium and polonium.  Their group is called part of the nonmetallic elements. Selenium was put in their group because it is similar to these elements in terms of forms and compounds. According to Anne Marie Helmenstin “Selenium is used in xerography to copy documents and in photographic toner. It is used in the glass industry to make ruby-red colored glasses and enamels and to decolorize glass. It is used in photocells and light meters. Because it can convert AC electricity to DC, it is widely used in rectifiers. Selenium is a p-type semiconductor below its melting point, which leads to many solid-state and electronics applications. Selenium is also used as an additive to stainless steel.” If I was to put that paragraph into my own words I would have to say that selenium is very useful in a glass industry. In my opinion selenium is not one of the most important or outstanding elements on the table but it did catch my eye. 

Websites: 

Gold- http://www.buzzle.com/articles/gold-the-element.html

Selenium- http://chemistry.about.com/od/elementfacts/a/selenium.htm