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THE PERIODIC TABLE
HOMEWORK HELP SOS NEED ANSWER NOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

2007-01-17 10:24:59 · 3 answers · asked by keke 1 in Education & Reference Homework Help

3 answers

Please check my other post. The two groups all the way on the right are halogens and the noble gases.

I'm sure wikipedia has quite a bit on both of them as well.

http://en.wikipedia.org/wiki/Periodic_table
http://en.wikipedia.org/wiki/Halogen
http://en.wikipedia.org/wiki/Noble_gas

2007-01-17 10:29:40 · answer #1 · answered by Ace 4 · 0 0

ok...here....i wrote this when i was in 6th grade...so if ur in 7th or 8th i feel bad for you...
What is the Periodic Table of The Elements?

The periodic table is the most important chemistry reference there is. It arranges all the known elements in an informative array. Elements are arranged left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.
The different rows of elements are called periods. The period number of an element signifies the highest energy level an electron in that element occupies (in the unexcited state). The number of electrons in a period increases as one traverses down the periodic table; therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases.
Using the data in the table scientists, students, and others that are familiar with the periodic table can extract information concerning individual elements. For instance, a scientist can use carbon's atomic mass to determine how many carbon atoms there are in a 1 kilogram block of carbon.

People also gain information from the periodic table by looking at how it is put together. By examining an element's position on the periodic table, one can infer the electron configuration. Elements that lie in the same column on the periodic table (called a "group") have identical valance electron configurations and consequently behave in a similar fashion chemically. For instance, all the group 18 elements are inert gases.

Periodic Table first discovered in 1869 by Dimitri I. Mendeleyev is a way of presenting all the elements so as to show their similarities and differences. The elements are arranged in increasing order of atomic number as you go from left to right across the table. The horizontal rows a called periods and the vertical rows, groups.
A noble gas is found at the right hand side of each period. There is a progression from metals to non-metals across each period. Elements found in groups (e.g. alkali, halogens) have a similar electronic configuration. The number of electrons in outer shell is the same as the number of the group (e.g. lithium 2·1).
The block of elements between groups II and III are called transition metals. These are similar in many ways; they produce colored compounds, have variable valence and are often used as catalysts. Elements 58 to 71 are known as lanthanide or rare earth elements. These elements are found on earth in only very small amounts.
Elements 90 to 103 are known as the actinide elements. They include most of the will known elements which are found in nuclear reactions. The elements with larger atomic numbers than 92 do not occur naturally. They have all been produced artificially by bombarding other elements with particles.

Element - Chemical elements are the fundamental materials of which all matter is composed. From the modern viewpoint a substance that cannot be broken down or reduced further is, by definition an element.

2007-01-17 18:31:16 · answer #2 · answered by brianna e 1 · 0 0

I presume you mean group VIII (8). These are the 'noble' gases. Since they have a full outer electron shell they are unreactive, and do not combine with other elements.

2007-01-17 18:29:53 · answer #3 · answered by Fitz 3 · 0 0

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