Periodic events happen at predictable intervals. The events are related and can be grouped into categories. The Light Rail trains follow a predetermined schedule and a predetermined route. The trains make the same stops at approximately the same time every day.

What else is an example of a periodic event? What is an easy way to keep track of periodic events? What are some examples of non-periodic events?

The Periodic Table Objectives: I will be able to: explain how the Periodic Table was developed. interpret an element key. explain how the Periodic Table is organized.

The Periodic Table Vocabulary: period: horizontal row of elements in the periodic table whose properties change gradually and predictably. group: family of elements with similar physical or chemical properties that occupies the same column in the periodic table.

The Periodic Table metal: element that is a good conductor of electricity and heat, is usually solid at room temperature, and is usually shiny, ductile, and malleable. ductile: capable of being drawn out into wire or thread. malleable: capable of being shaped or formed, as by hammering or pressure. nonmetal: element that is a poor conductor of heat and electricity and may be a gas or a brittle solid at room temperature.

The Periodic Table metalloid: element that shares some properties with metals and some with nonmetals. atomic number: number of protons in the nucleus of an atom of a specific element. atomic mass: the average mass (weight) of one atom of a particular element, based on the average mass of all the element's stable isotopes.

Development of the Periodic Table Early civilizations were familiar with a few of the elements, such as gold and silver. Nineteenth century (1800’s) scientists searched for new elements and discovered 55 by 1830. Were there more elements?

Development of the Periodic Table Russian chemist Dmitri Mendeleev noticed patterns when he arranged the elements in order of their atomic mass. The patterns had to do with the properties of the elements. In 1869 he proposed a table of the known elements based on the recurring patterns.

Development of the Periodic Table Mendeleev realized that the groupings in his table only worked if there were undiscovered elements. He left gaps in the table for these undiscovered elements. Mendeleev even predicted the properties for six of the undiscovered elements.

Development of the Periodic Table Mendeleev’s Predictions: Property Predicted Actual Ekaaluminium Gallium atomic mass 68 69.72 density (g/cm³) 6.0 5.904 melting point (°C) Low 29.78

Development of the Periodic Table English physicist Henry Moseley improved Mendeleev’s table by arranging it according to atomic number instead of atomic mass. Moseley’s periodic table made it easier to predict undiscovered elements. Moseley’s table did a better job of showing missing elements.

 What is a “periodic event”? What is the difference between atomic number and atomic mass? Putting the known elements into repeating rows allowed Mendeleev and others to predict what? events that happen at predictable intervals Atomic number is just the number of protons, atomic mass is protons + neutrons They could predict missing, unknown elements

The Modern Periodic Table The Periodic Table is organized by periods (the rows) and groups (the columns). The properties of the elements in each period change gradually and predictably. The elements in each group share similar physical and chemical properties. http://www.youtube.com/watch?v=1xc0SMMCs08 http://www.youtube.com/watch?NR=1&v=Z7Ilxsu-JlY&feature=fvwp

The Modern Periodic Table Period 2 Trends Atomic Mass Density g/cm3 Melting Point oC Boiling Point oC Physical State Li 6.941 0.534 180.5 1342 Solid Be 9.012 1.85 1278 2970 B 10.811 2.34 2079 2550 C 12.011 2.25 3367 4827 N 14.007 .00125 -209.9 -195.8 Gas O 15.999 .00143 -218.4 -183.0 F 18.998 .00169 -219.6 -188.1 Ne 20.179 .00089 -248.7 -246.0

The Modern Periodic Table The Periodic Table has 7 periods and 18 groups of elements. Period 1 has only 2 elements. Periods 2 & 3 have 8 elements each. Periods 4 & 5 have 18 elements each. Period 6 & 7 have 32 elements.

Sections of the Periodic Table The Periodic Table can be divided into two sections. Section 1 consists of groups 1, 2, & 13-18 and is called the representative elements and includes the metalloids and nonmetals. Section 2 consists of groups 3-12 and are called the transition elements and include the metals. The inner transition elements are placed below the table so the table takes up less space.

Metals, Nonmetals, & Metalloids Metals are found in groups 3-12 in the Periodic Table. Properties of Metals: Solid physical state (1 exception, Hg) High melting points (2 exceptions, Hg, Ga) Good conductors of heat & electricity Have luster (reflects light) Are ductile and malleable.

Metals, Nonmetals, & Metalloids There are only 17 nonmetals. H, He, C, N, O, F, Ne, P, S, Cl, Ar, Se, Br, Kr, I, Xe, Rn Properties of nonmetals: Poor conductors of heat & electricity Usually either gases or brittle solids Many are required for living organisms

Metals, Nonmetals, & Metalloids Metalloids share properties from both metals and nonmetals. Trends or patterns are harder to see in metalloids.

Element Keys Each element on the Periodic Table has an element key. The element key provides information about the element such as: 1. element name 2. element symbol 3. atomic number 4. atomic mass 5. boiling point 6. melting point 7. physical state at room temperature

Element Keys Element symbols are either one or two letter abbreviations. The abbreviation is based on the element name, the name in Greek or Latin, famous people, or geographic locations. Periodic Table of Rock https://www.youtube.com/watch?v=xbf0HdLwLZA&feature=related Elements by Tom Lehrer https://www.youtube.com/watch?v=SmwlzwGMMwc&NR=1

Review Who created the periodic table? Dmitri Mendeleev in 1869. Who improved it? Henry Moseley What do we call the rows and columns? rows = periods columns = groups

Review What are the three main types of elements? metals, nonmetals, and metalloids What are the two main sections of the periodic table? representative elements and transition elements What information does the element key contain? element name, element symbol, atomic number, atomic mass, boiling point, melting point, physical state at room temperature

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Web Links http://www.youtube.com/watch?v=h2U4Taoqqn8&feature=related http://www.youtube.com/watch?v=xbf0HdLwLZA&feature=related http://www.youtube.com/watch?v=GFIvXVMbII0 http://www.youtube.com/watch?v=SmwlzwGMMwc&NR=1 http://www.youtube.com/watch?v=d0zION8xjbM&feature=fvw http://www.youtube.com/watch?v=zGM-wSKFBpo&feature=related http://www.periodicvideos.com/ http://periodictable.com/

Web Links http://www.webelements.com/ http://www.mii.org/periodic/LifeElement.html http://www.uky.edu/Projects/Chemcomics/ http://sciencespot.net/Pages/classchem.html http://www.bayerus.com/MSMS/MSMS_Education_Resources_Activities/ResourcesSTP/Sciencefun/PeriodicTable/PeriodicTableIntro.aspx http://www.learner.org/interactives/periodic/index.html http://www.youtube.com/watch?v=SXx2VVSWDMo&NR=1

Assignment On a separate sheet of paper: Put the title “Introduction to the Periodic Table” at the top center of the page. Put your name, date, and class period in the top left corner. Write out and answer questions 1-5 on the next two slides.

Use the elements in period 4 to show how the physical state of the elements changes as the atomic number increases across a period. What are the two sections of the periodic table? Where are the metals located in the periodic table? The nonmetals? The metalloids? How would the modern periodic table be different if elements were still arranged by average atomic mass instead of atomic number? Give two specific examples.

Prepare a circle graph of the most abundant elements by weight in Earth’s crust. What percent by weight of the crust is from metals? Metalloids? Nonmetals? Element % oxygen 46.6 sodium 2.8 silicon 27.7 potassium 2.6 aluminum 8.1 magnesium 2.1 iron 5.0 other 1.5 calcium 3.6