Chapter 5 The Periodic Table Overview
Overview The Language of Chemistry • The elements, their names, and symbols are given on thePERIODIC TABLE • How many elements are there?
The Periodic Table Dmitri Mendeleev (1834 - 1907) See Pages 132 & 133
Glenn Seaborg(1912-1999 ) • Discovered 8 new elements. • Only living person for whom an element was named.
Overview Periods in the Periodic Table
Overview Groups in the Periodic Table Elements in groups react in similar ways!
Overview Regions of the Periodic Table
The Periodic Table Dmitri Mendeleev (1834 - 1907) See Pages 132 & 133
5.1 The Periodic Table Organizing Anything • Classification is arranging items into groups or categories according to some criteria. • The act of classifying creates a pattern that helps you recognize and understand the surroundings.
The Periodic TableOrganizing the Elements • Can be arranged by atomic number or atomic mass. • 1, 2, 3, 4, 5, 6, etc. • 1.008, 4.003, 6.941, etc. • Can be arranged by physical or chemical properties. • Radius of atom, ionization potential etc.
Organizing the Elements • The atomic mass is usually placed under the symbol for the atom. • The periodic table is arranged by atomic number: 1, 2, 3, 4, etc., with new rows placed when there is a big change in a property. Atomic Number 6 Mass Number 12 Atomic Mass C C Atomic Number 6 12.0
Organizing The Elements by Dmitri Mendeleev • Gave us a functional scheme with which to classify elements. • Mendeleev’s scheme was based on chemical properties and the mass of the elements. • It was noticed that the chemical properties of elements increased in a periodic manner. • He used the table to predict the occurrence and chemical properties of elements which had not yet been discovered.
Mendeleev’s Periodic Table • He left blank spaces in his table when the properties of the elements above and below did not seem to match. • Mendeleev used the properties of existing elements to predict properties of undiscovered elements.
Mendeleev’s Periodic Table • He used Eka and the name of an known element. (eka-aluminum) • Properties like aluminum • He predicted the properties based on the known elements properties. • When the unknown elements were discovered, it was found that Mendeleev had closely predicted the properties of the elements as well as their discovery. (This showed the usefulness of his table)
Section 5.1 a. Mendeleev arranged the elements in order of increasing mass so that elements with similar properties were in the same column.
Section 5.1 b. Mendeleev used the properties of existing elements to predict properties of undiscovered elements.
Section 5.1 C.The close match between Mendeleev’s predictions and the actual properties of new elements showed how useful his periodic table could be.
Other Periodic Tables Some periodic tables that look quite different from the one in your book. Look at Theodore Benfey’s version of a periodic table, which he made in 1960.
5.2 The Modern Periodic Table • The periodic table is made up of rows of elements and columns. • An element is identified by its chemical symbol. • The number above the symbol is the atomic number • The number below the symbol is the atomic mass of the element. • A row is called a period • A column is called a family
(A) Periods of the periodic table • (B) families of the periodic table
5.2 Periodic Law • When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals.
Metals, Nonmetals, Metalloids • The broken line represents the boundary between metals and nonmetals. • To the right of the broken line, nonmetals. • To the left of the broken line, metals. • Next to the broken line on the right are the metalloids.
5.2 Metals • Found to the left of the “diagonal line” • lose electrons in chemical reactions • A metal has the following properties. • Metallic luster • High heat and electrical conductivity. • Malleability, able to be rolled or pounded into a thin sheet. • Ductile, can be pulled into a wire. • Form alloys (solid-solution of one metal in another)
Transition Elements Lanthanides and actinides Iron in air gives iron(III) oxide
The Transition Elements An important use of transition elements is as pigments in paints and glasses
5.2 Nonmetals • Found to the right of the “diagonal line” • Like to gain electrons from metals, or share electrons among themselves • A nonmetal has the following properties • No metallic luster • Poor conductor of heat and electricity. • When it is a solid it is brittle so it cannot be pounded or pulled into a wire.
5.2 Metalloids • Elements next to the “diagonal line” or dividing line between metals and nonmetals • B, Si, Ge, As, Sb, and Te • Physical properties of a metal (can be “convinced” to conduct electricity) and chemical properties of a nonmetal
Chemical Families • The first 2 chemical families of the periodic table: • the alkali metals (IA) • the alkaline earth metals (IIA)
Group 1A: Alkali Metals Reaction of potassium + H2O Cutting sodium metal
Group IA - The Alkali Metals(Li, Na, K, Rb, Cs, Fr) • Alkali metals because they react with water to from an alkaline solution • Lose 1 valence electron • Highly reactive Reaction of potassium + H2O
Group 2A: Alkaline Earth Metals Magnesium Magnesium oxide
Group IIA - The Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra) • Not as reactive as Group IA • Are soft metals like Earth • Lose 2 valence electrons • Also react with H2O but less violently • Ca(s) + 2H2O(l) Ca(OH)2(aq) + H2(g)
Group IIA - The Alkaline Earth Metals(Be, Mg, Ca, Sr, Ba, Ra) Various forms of CaCO3
flashbulbs Group IIA - The Alkaline Earth Metals(Be, Mg, Ca, Sr, Ba, Ra) • Reaction of magnesium with oxygen Mg(s) + O2(g) MgO(s)
Other Group/Families • Four group/families of the periodic table: • Boron (IIIA) • Carbon (IVA) • Nitrogen (V) • Oxygen (VIA)
Group IIIA - The Boron Family(B, Al, Ga, In, Tl) • Boron is mined in the form of Borax, and is used in laundry soap • Laboratory glassware contains borosilicates
Group IIIA - The Boron Family(B, Al, Ga, In, Tl) • Aluminum metal is the most abundant metal in the earth’s crust and has many uses
Group IIIA - The Boron Family(B, Al, Ga, In, Tl) • Gallium Arsenide is used in the manufacture of computer chips
Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb) • Carbon is essential for life and is found in all organic molecules
Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb) • Carbon is found in different structures or ALLOTROPES - graphite, one of the softest substances known, and diamond, the hardest
Quartz or SiO2 Elemental Si is used in the semiconductor industry Group IVA - The Carbon Family(C, Si, Ge, Sn, Pb)
A control rocket on the Space Shuttle uses hydrazine, N2H4, as fuel There are two varieties of P, red and white. Group VA - The Nitrogen Family(N, P, As, Sb, Bi)
Group VIA - The Oxygen Family(O, S, Se, Te, Po) Stratospheric ozone shields us from harmful UV radiation. Ozone is destroyed by Cl-containing molecules used in refrigeration The ozone “hole” over Antarctica
Chemical Families • The last 2 chemical families of the periodic table: • halogens (VII) • the noble gases (VIIIA)
Halogens need only one electron to fill their outer shell They are very reactive. Br2 and I2 Group VIIA - The Halogens(F, Cl, Br, I, At)