Introduction to the Periodic Table. Chapter 4.5

Transcription

1 Introduction to the Periodic Table Chapter 4.5

2 History of the Periodic Table Dmitri Mendeleev, Russian Chemist Organized the first periodic table (1860) Organized elements according to properties 1.Ordered by atomic mass 2.Periodic patterns

3 1.Arranged in vertical periods 1.Placed some elements out of order 1.Fit into family similar chemical properties 2.Left openings predicted elements properties 2.Led to the modern periodic table organized by atomic number

4 1.Modern periodic table 1.Moseley (1911) 1.Ordered atoms by atomic number 2.Periodic law: The physical and chemical properties of the elements are periodic functions of their atomic numbers. 2.Periodic table: arrangement of the elements in order of the atomic numbers so that elements with similar properties fall in the same group

5 Families & Periods Elements are arranged so that each vertical column, or family, have similar physical and chemical properties. (also called groups) -Groups referred to as number above column. -Also have specific names. Arrange by increasing atomic number across the row, periods.

6 Organization of the Periodic Table Periodic Table is arranged by metallic character. *** Note Hydrogen is a nonmetal!

7 Properties of Metals Metals (left of P.T/staircase) usually have common properties: usually silver-gray (except copper and gold) good conductors of heat and electricity all but one are solid at room temperature. Malleable (can be bent or hammered flat) Ductile-can be drawn into wire High melting point Show reaction with acids Lustrous (shiny appearance, reflect light when polished)

8 Properties of Nonmetals Nonmetals: (found right of staircase) Usually dull, do not reflect light Brittle and cannot be hammered into sheets Poor conductors of electricity and heat Little or no reaction with acids Low melting points Either solids or gas (bromine-exception =liquid)

9 Properties of Nonmetals Cont. Most of your body s mass is made of oxygen, carbon, hydrogen, nitrogen and phosphorus. Calcium, a metal, and other elements make up the remaining four percent of your body s mass.

10 Metalloids/Semimetals Found on both sides of staircase (except Aluminum) B, Si, Ge, As, Sb, Te, (Po book doesn t list) show properties of both metals and nonmetals not good conductors of electricity When mixed with small amounts of other elements the conductivity of metalloids increase Silicon solid, brown or gray-black, very hard, very brittle, expands when freezes. Basis for computer chips. Arsenic sublimates (goes directly from solid to gas) Tellurium-very rare, silvery-white and poisonous

11 Families of the Periodic Table Periodic Table is arranged by Families Family Names Alkali Metals Alkaline Earth Metals Halogens Noble Gases Transition Metals Lanthanides Actinides

12 Alkali Metals The elements in Group 1 of the periodic table are the alkali metals. Group 1 metals are shiny, malleable, and ductile. They are also good conductors of heat and electricity. However, they are softer than most other metals. (Can cut with a knife) The alkali metals are the most reactive of all the metals. They react rapidly, sometimes violently, with oxygen and water. Alkali metals don t occur in nature in their elemental form and are stored in substances that are unreactive, such as an oil. os/search?q=sodium+in+wa ter&&view=detail&mid=c2 9E4E90CA76831FCBEAC29E 4E90CA76831FCBEA&rvsmi d=246c358b74c7cbd63ab5 246C358B74C7CBD63AB5&f sscr=0&form=vdqvap s/search?q=sodium+in+wate r&&view=detail&mid=a02e 7C2E479B21A49228A02E7C 2E479B21A49228&rvsmid=2 46C358B74C7CBD63AB5246 C358B74C7CBD63AB5&fsscr =0&FORM=VDFSRV

13 Alkaline Earth Metals The alkaline earth metals make up Group 2 of the periodic table. Tarnish in air, not very hard Gray-white luster Each atom of an alkaline earth metal has two electrons in its outer energy level. * Calcium 5 th most abundant element in Earth s crust.

14 Transition Metals * Transition elements are those elements in Groups 3 through 12 in the periodic table. They are called transition elements because they are considered to be elements in transition between the Main Group elements. Transition elements are familiar because they often occur in nature as uncombined elements. * Very hard with high melting and boiling points. Transition elements often form colored compounds. Gems show brightly colored compounds containing chromium. * Iron makes up almost all of earth s crust

15 Inner Transition Metals The two rows of elements that seem to be disconnected from the rest on the periodic table are called the inner transition elements. They are called this because like the transition elements, they fit in the periodic table between Groups 3 and 4 in periods 6 and 7, as shown.

16 Halogens Halogen lights contain small amounts of bromine or iodine vapor. Highly reactive! High electronegativity. Bromine-reddish-brown liquid, metallic luster as solid, nonmagnetic, toxic and corrosive! All know isotopes of Iodine are radioactive, sublimates Astatine occurs only as result of radioactive decay of heavier elements. tch?v=vyp8zhs9c5c

17 The Noble Gases The noble gases exist as isolated atoms. All gases at room temperature. Neon plasma glows reddish orange. Used to make signs. They are stable because their outermost energy levels are full. No naturally occurring noble gas compounds are known.

18 Blocks of Periodic Table The Periodic Table can be organized by blocks s Block p Block d Block f Block