If you like the ChemWiki, please "like" us on facebook, "share" us on Google+, or "tweet" about the project.
The Periodic Table is the key to all chemical reactions, bonding, orbitals ect. In this module i will be going over Metalloids(Halogens, noble gases, and other nonmetals) and Metals( Alkali metals, Alkali-earth metals, Transition metals, and Lanthanoids).
The basic principles of the periodic table depended on the discovery of elements. The periodic table was first constructed by Dmitri Ivanovich Mendeleev. He than arranged the table of increasing atomic mass. By doing this he felt that the periodic table can be used illustrate the trends and properties of the elements. Throughout the years many new elements have been discovered and been added to the table, but its still construted around the basic principles of Mendeleev design. Here is a picture Mendeleev table.
The periodic table is arranged in rows and columns. The rows, generally called a period, go across the table(1-7) and down the table(group 1,2, and 3A-8A). The atomic number on a periodic table is referred to as the letter z. As your going across the table from left to right atomic number z increases. The middle of the periodic table contains the Transition metals. Starting from element 58 going to element 71 is called the Lanthanides metals. Group 1A is called the Alkali metals, Group 2A is Alkaline-earth metals, group 7A is Halogens and Group 8A is the Noble Gases. Most elements in the periodic table are classified between two groups-Metals and Non-Metals. Metals are good conductors of electricity while most non-metals are bad conductors for heat and usually are gases at room temperature. Usually your non-metals are usually groups 7A and 8A.
The periodic table has many trends incorporated into it. The most common trends are atomic radii, Electronnegativity, Ionization energy, and Electron affinity. Atomic radius is related the size of the element. Generally the atomic radius decreases from left to right and increases from top to bottom. Next, Electron affinity is basically the ability of an atom to gain an electron. Generally the electron affinity increases as you move from left to right and increases as you go from bottom to top. Electronnegativity is the ablity to attract other electrons from different elements. Generally the electronnegativity increases from left to right and decreases from top to bottom. Last, Ionization energy is the ability to remove an electron from a gaseous element or an ionic element. The Ionization energies decrease as you move down a group and increase as you move across a period.
The periodic table can also explain what type of orbital a certain element would achieve. In order to predict what type of orbital an element would have, you need to know what the electron configuration of that element. The period is broken up into different type of orbitals that commonly range from s,p,d, and f orbitals.
In this module I'm not going to explain how to find the electron configuration for a certain element but as you can see, the periodic table predicts the atomic orbial for every element.
Metals are by far the largest group of elements. They consist of Alkali metals, Alkaline-earth metals, Transition metals, post-transition, and your lanthanoids. Metals are likely to lose electrons in order for them to become more stable. Metals are also very good conductors of heat and electricity.
Alkali Metals- Usually react with non-metals to from ionic compounds. They are usually +1 in their ionic state. For example, NaCl---(Na+)+(Cl-). This groupl is also very reactive and are not normally found in nature in there elemental state. Going back to the +1 charge they usually have in their ionic state, they usually have one valance electron in their outter shell, generally causing them to lose one electron to make them stable, giving them their +1 charge.
Alkaline-Earth Metals- They have 2 valance electrons in their outter shell. Generally they will lose these two electrons to become the most stable, giving them a +2 charge when they are in their ionic state. Some of the Alkaline-earth metals play an important role in biology. For example, Ca is found throughout your body, ususally in your bones.
Transtition Metals- This is the area of the periodic table where you get your d orbitals. Also are very good conductors of heat and electricity, but have a higher boiling point than most other metals. The transtition metals are have a lot of color when they form compounds.
Post-Transition metals- These metals include al,ga,ge,in,sn,sb,ti,pb,bi,po,uut,uuq,uup,uuh.
Lanthanoids- These metals are a part of the Transition Metals, but these are your f orbitals. We usually dont deal with to much Lanthanoids, because I believe most of them are man-made elements. These elements share almost the same characteristics as the element Lanthanum.
The non-metals include noble gases, halogens, C, N, O, P, S, and Se. These are very poor conductors of heat and electricity. They usually are anions in their ionic states. Most non-metals will have four, five, six, seven, or eight valance electrons in their outter shell. Causing them to either be -3,-2, or -1 in their ionic state.
Noble Gases- Noble gases are the most stable elements. They usually have their outter shell causing them to be the most stable elements. They are usually gases at room temperature. This group of elements don't like to lose or gain electrons, causing them to not want to interact with other elements.
Halogens- Halogens like to gain one electron which would give them the electron configuration of a noble gase. Usually Halogens are -1 in their ionic state. They have low melting and boiling points, but it does increases has you go down the group.
1.) Which element is considered a non-metal?
a.)Li B.)Cu C.) Al D.) Ne
2.)Which element has the highest electronegativity?
a.)C B.)F C.)Cs D.) H
3.) Which group has the most stable elements?
a.) Noble gases B.)Alkali metals c.)Halogens D.)Alkalin-earth metals
4.)What is the electron configuration for C?
5.)What is the electron configuration for Ni?
An NSF funded Project
By STEMWiki Hyperlibrary