Introduction to the Periodic Table Chapter 3
Objectives 3.1 • Outline the steps in the historic development of the periodic table • Predict similarities in properties of the elements by using the periodic table.
Key Terms 3.1 • Group (columns) • Period (rows) • Periodic law (atoms arranged by increasing atomic number)
Historical Perspective • Mendeleev credited with being the first to organize the periodic table (same guy who did the punnett square) • Really smart guy, left blanks in where he thought (knew) that another element would be discovered and predicted the properties of the element • Organized by mass • Modern organized by atomic number
Development of Periodic Table Mendeleev, for instance, predicted the discovery of germanium (which he called eka-silicon) as an element with an atomic weight between that of zinc and arsenic, but with chemical properties similar to those of silicon.
Historical Perspective • The periodic table is organized by groups. • Each group has similar properties (vertical columns) • Oxygen is similar to Sulfur is similar to Selenium • This is all because of having similar valence structures (which are again the electrons which do the interacting)
Development of Periodic Table • Elements in the same group generally have similar chemical properties. • Properties are not identical, however.
Development of Periodic Table Dmitri Mendeleev and Lothar Meyer independently came to the same conclusion about how elements should be grouped.
End 3.1 Notes. Can you? • Predict which elements share similar properties to Oxygen (O)? • Summarize how the periodic table is organized? • Compare how Mendeleev organized his table to the modern table?
Chapter 3.2 Objectives • Relate an element's valence electron structure to its position in the periodic table • Compare and contrast properties of metals, non-metals, and metalloids. • Use the periodic table to identify elements as metals, non-metals, and metalloids • Learn about 4 special families in the periodic table with associated properties
Metal Nonmetal Metalloid Semiconductor Conductor Insulator Transition Elements Lanthanide Actinide Alkali Metals Alkaline Earth Metals Halogens Noble Gases Key Terms 3.2
Properties of Metals • Luster • Conductors (Heat/Electrons) • Malleable • Ductile • Most are solid at room temperature • Loosely held valence electrons
Properties of Nonmetals • Insulators • Brittle • Dull • Many are gases at room temperature • Tightly held valence electrons
Metalloids • Have properties of both • Instead of thinking an element is purely a metal or only a nonmetal, think of the periodic table as a spectrum. • Lower left is the best metal, as you move towards the top right, you lose your metal properties and become more of a nonmetal • Metalloids are in the middle • What metal and nonmetal properties does Gold have?
Alkali Metals One Word: First Column
Alkaline Earth Metals Two Words: Second Column
Human Body Chemistry • Table 3-1. Estimated Atomic Compositionof the Lean 70-kg Male Human Body(compiled & adapted from [749, 751-752, 817]) • The human body consists of ~7 x 10^27 atoms arranged in a highly aperiodic physical structure. Although 41 chemical elements are commonly found in the body's construction (Table 3-1), CHON comprises 99% of its atoms. Fully 87% of human body atoms are either hydrogen or oxygen.
Human Body Chemistry • Calcium: Bones, teeth; essential for blood clotting and muscle contraction • Phosphorus: bones, teeth; component of nucleic acids (DNA) • Potassium: Present as K+ in all body fluids, essential for nerve action • Sulfur: Component of proteins, essential for blood clotting
Human Body Chemistry • Chlorine: Present as Cl- in all body fluids, important to maintaining salt balance • Sodium: Present as Na+ in all body fluids, essential for muscle and nerve action • Magnesium: In bones and teeth, essential for muscle action • CHNO make up over 99% of our body