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Dmitri Mendeleev organized the known elements into a table called the periodic table. He organized them by their increasing atomic masses.

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Presentation on theme: "Dmitri Mendeleev organized the known elements into a table called the periodic table. He organized them by their increasing atomic masses."— Presentation transcript:

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2 Dmitri Mendeleev organized the known elements into a table called the periodic table. He organized them by their increasing atomic masses.

3 Today we organize the elements by their increasing Atomic Number.

4 Insert copy of the periodic table.

5 Rows on the periodic table are called periods. All the elements listed in a row belong to the same period. There are 7 (seven) periods.

6 Columns in the periodic table are called groups or families. All elements in a group have similar properties.

7 Insert copy of the periodic table. The columns have been given an Arabic number. The columns are numbered 1 – 18 starting at the left and moving to the right. Please make sure that your periodic table has them numbered like this.

8 The outer most energy level is usually not full or complete. Valence electrons are important because they determine how an element will react with other substance. These electrons in the outer energy level are called Valence electrons. Valence Electrons

9 Group 1 and 2 the number of Valence electrons in the outer energy level will match the group number. Insert picture of periodic table.

10 Groups 3 through 12 do not follow any particular rule to determine the number of Valence electrons. Insert picture of periodic table.

11 Group 13 to 18 – The Valence electrons for each of these is the group number less 10. For example Group 14 – 10 = 4 Valence electrons. Insert picture of periodic table.

12 Elements whose atoms gain, lose or share electrons are reactive and they combine to form the many compounds we use in our daily lives.

13 Elements are categorized as metals, nonmetals or metalloids. Metals: An element that has luster, is malleable and ductile, and is said to be a good conductor of heat and electricity.

14 Luster describes the way a surface reflects light…therefore metallic luster would be shiny like a metal object. Malleable means to be able to press or pound the substance into sheets or different shapes. What is luster, malleable and ductile? Ductile means that the substance can be drawn out into thin wires.

15 Elements are categorized as metals, nonmetals or metalloids (cont’). Nonmetals: an element that is usually a gas or a brittle solid at room temperature. It is a poor conductor of heat and electricity.

16 Elements are categorized as metals, nonmetals or metalloids (cont’). Metalloid: an element that shares some characteristics or properties with both metals and nonmetals.

17 Group 1 and 2 Elements: These elements are so reactive that they are only found combined with other elements in nature.

18 3 Li Lithium Na Sodium K Potassium Rb Rubidium Cs Cesium Fr Francium Group 1: Alkali Metals Soft – can be cut with a knife Shiny and silver colored Low Density (some will even float) Most reactive of the metals Valence electrons = 1 Reacts violently with water forming a hydrogen gas Compounds from these are very useful such as NaCl

19 4 Be Beryllium Mg Magnesium Ca Calcium Sr Strontium Ba barium Ra Radium 226 Group 2: Alkaline- Earth Metals Very reactive but not as reactive as Alkali Metals. Silver colored More dense than Group 1 metals Valence electrons = 2 Useful compounds include: Calcium compounds such as cement, plaster, chalk, and YOU.

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21 Group 3 to 12: Transition Metals Do not lose their valence electrons as easily as groups 1 & 2. Less reactive than Alkali and Alkaline Earth metals Shiny Good conductors of electricity Higher density and melting points (except mercury) than Group 1 and 2

22 Group 3 to 12: Transition Metals (cont’.) Lanthanides: The first row underneath the periodic table: Shiny, reactive, many are used in the production of steel. Actinides: The second row underneath the periodic table: These elements are all radioactive and unstable.. Note: Elements found after 94 (Plutonium) are man made and not found in nature

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24 5 B Boron Al Aluminum Ga Gallium In Indium Tl Thallium Group 13: Boron Group Reactive Valence electrons = 3 Contains 1 Metalloid and 4 Metals Solid at room temperature Aluminum is the most abundant in this group and the most common in the Earth’s crust

25 6 C Carbon Si Silicon Ge Germanium Sn Tin Pb Lead Group 14: Carbon Group Reactivity varies in this group depending on the element Valence electrons = 4 This group contains 2 metals, 1 nonmetal and 2 metalloids. Many forms found uncombined in nature such as diamonds Compounds are very useful: proteins, fats, carbohydrates, computer chips.

26 7 N Nitrogen P Phosphorous As Arsenic Sb Antimony Bi Bismuth Group 15: Nitrogen Group Reactivity varies in this group depending on the element Valence electrons = 5 Group contains 1 metal, 2 Nonmetals, and 2 metalloids Phosphorous is very reactive and only found in nature combined with other elements. All but nitrogen are solid at room temperature. Nitrogen makes up 78% of our atmosphere. Generally unreactive.

27 8 O Oxygen S Sulfur Se Selenium Te Tellurium Po Polonium 209 Group 16: Oxygen Group More reactive than group 15 Valence electrons = 6 Group contains 1 Metals, 3 Nonmetals and 1 Metalloids Sulfur is found in nature and is used to make sulfuric acid, a very commonly used chemical in industry. All but oxygen are solid at room temperature. Oxygen makes up 21% of the Earth’s Atmosphere Oxygen is very reactive and combines with many other elements especially metals Rust is the result of the oxidation of metal.

28 9 F Fluorine Cl Chlorine Br Bromine I Iodine At Astatine 210 Group 17: Halogen Group Very reactive Valence electrons = 7 Nonmetal group Poor Conductors of electricity and heat React violently with alkali metals to form salts Never found uncombined in nature Atoms of these elements only need to gain 1 electron to fill their outer shell Chlorine and Iodine are both in this group and can be combined to make disinfectants.

29 2 He Helium Ne Neon Ar Argon Kr Krypton Xe Xenon Rn Radon 222 Group 18: Noble Gas Group Non-reactant Valence electrons = 8 Outermost energy shell is full Colorless, odorless gases at room temp. Under normal conditions they do not react with other elements All found on Earth in very small amounts Argon is the most common in the group Their non-reactivity makes them very useful for light bulbs, helium for blimps and weather balloons.

30 1 H Hydrogen Hydrogen Stands Alone: Properties do not match the properties of any single group Valence Electrons = 1 Easily looses that one valence electron Physical properties are like the nonmetal group Most abundant element in the Universe Its reactive nature makes it useful as a fuel for rockets.

31 Insert picture of periodic table.


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