Periodic Table - PDF

Periodic Table of Elements Arrangement of the Periodic Table Lesson After going through this module, you are expected to 1. identify the scientists who contributed in the development of the periodic table 2. explain how elements are arranged in the modern periodic table...

Periodic Table of Elements Arrangement of the Periodic Table Lesson After going through this module, you are expected to 1. identify the scientists who contributed in the development of the periodic table 2. explain how elements are arranged in the modern periodic table 3. recognize the importance of the arrangement of the periodic table 4. differentiate the general classification of elements 5. compare and contrast the different representative elements 6. appreciate the importance of the periodic table The periodic table of elements is a method of showing the chemical elements in a table with the elements arrange in order of increasing Atomic Number together with its Element’s Name, Element’s Symbol and Atomic Weight. The arrangement of the table shows as well as the existing chemical properties of the elements.  Who created it? Alchemy refers to both an early form of investigation of nature and early philosophical and spiritual disciplines.  Alchemists They preserved their work with confidentiality. It had influenced modern chemists to use symbols for facilitating writing and for convenience.  John Dalton John Dalton started the use of symbols in representing atoms of different elements. What do all the numbers mean ?  Jons Jacob Berzelius He invented the system of chemical symbols. Origin of Periodic Table  Antoine Lavoisier First Classification – Simple Substances He arranged the list of his elements into four categories: Acid-making elements Gas-like elements Metallic elements Earthy elements  Johannes Dobereiner Triads He studied three elements and noticed similarities among the properties of metals. He predicted that there is closeness among the atomic masses of elements Ca, Ba, and Sr  A. E. de Chancourtois Telluric Helix He had the idea to plot the elements in a spiral around the surface of the cylinder divided into 16 vertical sections, according to elements’ atomic masses.  John Newlands Octaves He arranged all the elements according to their atomic masses, starting with Lithium. He noticed that the ninth element has the same property with the first element.  Dmitri Mendeleev and Julius Meyer Periodic Property Graph It provides a more detailed tabulation of the elements based on their periodic properties. The properties of elements are periodic functions of their atomic masses. – Periodic Law  Henry Moseley Atomic Numbers He suggested that atomic mass is not the property that governs periodicity. He uses experiments on the X-ray emission spectra. Who created it? The quest for a systematic arrangement of the elements started with the discovery of individual elements. By 1860 about 60 elements were known and a method was needed for organization. In 1869, Russian chemist Dimitri Mendeleev proposed arranging elements by atomic weights and properties. The table contained gaps but Mendeleev predicted the discovery of new elements.  So how is it arranged? The genius of the periodic table “is that it is organized like a big grid. The elements are placed in specific places because of the way they look and act. You've got Your Periods... Even though they skip some squares in between, all of the rows go left to right. When you look at a periodic table, each of the rows is considered to be a different period  Periods = Rows In the periodic table, elements have something in common if they are in the same row. All of the elements in a period have the same number of atomic orbitals. And you got your groups… The periodic table has a special name for its columns, too. When a column goes from top to bottom, it's called a group.  Groups = Columns The elements in a group have the same number of electrons in their outer orbital. There are some exceptions to the order when you look at the transition elements, but you get the general idea. What do all the numbers mean ? Other than periods and groups, the table is divided into families. ALKALI METALS very reactive metals that do not occur freely in nature malleable, ductile, good conductors of heat and electricity. can explode if they are exposed to water ALKALINE EARTH METALS metals very reactive not found free in nature TRANSITION METALS ductile and malleable, and conduct electricity and heat iron, cobalt, and nickel, are the only elements known to produce a magnetic field.  RARE EARTH ELEMENTS many are man-made OTHER METALS are ductile and malleable are solid, have a high density  METALLOIDS have properties of both metals and non-metals some of the metalloids are semi-conductors. This means that they can carry an electrical charge under special conditions.  NON-METALS not able to conduct electricity or heat very well very brittle Do not reflect light. From www.science-class.net HALOGENS "halogen" means "salt-former" and compounds containing halogens are called "salts" exist in all three states of matter NOBLE GASES do not form compounds easily Happy/Inert Elements (Full outer shells) From www.science-class.net