Activity 19.1.2– Arranging elements by physical properties
(1) Abundance: Coins and jewelry are normally made of rare elements so that they have intrinsic value and are difficult to counterfeit. By contrast, metals used in construction are abundant and inexpensive, keeping construction costs down. Sort (arrange) the elements database (table 19.2, available online at www.sciencesourcebook.com) by abundance in the Earth’s crust and determine if these generalizations hold true. Research the relative abundance of gold, iron, copper, aluminum, silver, and platinum and determine which are better suited for coins or construction on the basis of this single criteria.
(2) Element symbols: Most element symbols are derived from the first one or two letters of the element name. For example, the symbol for oxygen is O and the symbol for helium is He. This is not true for all elements, however. For example, the symbol for potassium is K, even though there is no such letter in the name. Determine if there is a correlation between the date of discovery and the symbol/name convention. Sort (arrange) the elements by date of discovery, and compare the element names with the symbol names. Is there greater correlation between the names of elements and their symbols for recently discovered elements, or for ones discovered many years ago? Explain.
(3) Ionization potential: Ionization potential (energy) is the energy required to remove an electron from a neutral atom. Elements with a low ionization energy easily loose electrons and become cations, while those with high ionization energy hold on to their valence electrons much more firmly. Where in the periodic table are the elements located that frequently lose valence electrons to become cations? Sort the elemental data from low to high ionization potential (ascending sort). Which elements have the lowest ionization energy, and where are they found in the periodic table? Which elements have the highest ionization energy, and where are they found?
Other resources
- Element display
- Periodic properties (videos)
- Finding the missing elements (Hands-On Chemistry 2.2.1)