CHM/110
William De Vorick
June 30, 2014
Atoms, Molecules, and Elements
Demetri Mendeleev was trying to organize the elements into a table by weight when he noticed that as the weights increase occasionally the properties of one element would resemble those of an element he already listed so he placed these elements in a column under the ones they resembled chemically ( Capri, PhD, 2003). Each chemical in the vertical rows on the periodic table are considered families or groups because they have properties that are similar to each other.
All the chemicals in group 1A of the periodic table are considered alkali metals. Alkali metals are similar in that each of them has only one atom in the outermost shell and they are very reactive when combined with other elements. All elements in column 7A are halogens. Halogens are also highly reactive oxidizing agents that are called “salts”. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1 (Bodner Research Web, n.d.). Noble gases can be found in Column 8A. These elements are all considered to belong in this column because they are all gases that are considered unreactive due to their shells being closed. The RSC.org (n.d.) website states “and can all be found in the smallest of quantities the atmosphere itself”. These gases according to the Chemical Elements.com (1996-2009) website, “have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable.” Due to Mendeleev’s structure in his periodic table, the position of the elements due to their similar characteristics shows their reactive or non-reactive qualities.
The Halogens are all atomic elements because they can all be found in nature. If you were to combine two or more of these nonmetals, you would get a molecular compound such as . The first being Ammonia and the later of course water. A molecule is a chemically bonded unit of
References: Bodner Research Web. (n.d.). The Chemistry of Halogens. Retrieved 5/5/2011 from http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch10/group7.php Capri, Ph.D, A. (2003). The Periodic Table of Elements. Vision Learning. Retrieved 5/14/2011 from http://www.visionlearning.com/library/module_viewer.php?mid=52 ChemicalElements.com. (1996-2009). Periodic Table: Noble Gases. Retrieved from http://www.chemicalelements.com/groups/noblegases.html Clark, J. (2000). Molecular Structures. ChemGuide.com. Retrieved from http://www.chemguide.co.uk/atoms/structures/molecular.html RSC.org. (n.d.). Group 18- The Noble Gases. Retrieved from http://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupviii_data.html Tro, N. J. (2009). Introductory chemistry. (3rd ed.). Upper Saddle River, NJ: Pearson/Prentice Hall.