Chapter 4 Lecture Basic Chemistry Fourth Edition Chapter

Chapter 4 Lecture Basic Chemistry Fourth Edition Chapter 4 Atoms and Elements 4. 2 The Periodic Table Learning Goal Use the periodic table to identify the group and the period of an element; identify the element as a metal, a nonmetal, or a metalloid. © 2014 Pearson Education, Inc.

The Periodic Table In 1872, Dmitri Mendeleev • created the periodic table • arranged elements by increasing atomic mass • arranged elements into groups with similar properties © 2014 Pearson Education, Inc.

The Periodic Table © 2014 Pearson Education, Inc.

Periods and Groups On the periodic table • elements are arranged according to similar properties in vertical columns called groups • periods are horizontal rows of elements Periods 1 contains two elements: H and He Periods 2 and 3 each contain eight elements: Periods 2 – Li, Be, B, C, N, O, F, He Periods 3 – Na, Mg, Al, Si, P, S, Cl, Ar © 2014 Pearson Education, Inc.

Periods and Groups © 2014 Pearson Education, Inc.

Group Numbers, written at the top of each vertical column, are written two ways: • The letter A is used for the representative elements 1 A to 8 A and the letter B for the transition elements. • The numbers 1– 18 are used for the columns from left to right. © 2014 Pearson Education, Inc.

Group Numbers © 2014 Pearson Education, Inc.

Representative Elements – Groups and Names Representative elements include • Group 1 A (1), called Alkali metals Li, Na, K, Rb, Cs, and Fr • Group 2 A (2) called Alkaline earth metals Be, Mg, Ca, Sr, Ba, and Ra • Groups 3 A (13), 4 A (14), 5 A (15), and 6 A (16) • Group 7 A (17), called Halogens F, Cl, Br, I, and At • Group 8 A (18), called Noble gases He, Ne, Ar, Kr, Xe, and Rn © 2014 Pearson Education, Inc.

Representative Elements Group 1 A (1) Alkali metals Group 7 A (17) Halogens Chlorine 1 Cl 22, bromine 1 Br 22, and iodine 1 l 22 are halogens from Group 7 A 1172. Lithium 1 Li 2, sodium 1 Na 2, and potassium 1 K 2 are some alkali metals from Group 1 A 112. © 2014 Pearson Education, Inc.

Metals, Nonmetals, and Metalloids The heavy zigzag line on the periodic table separates the

Metals, Nonmetals, and Metalloids Most metals are shiny solids, such as copper (Cu), gold (Au), and silver (Ag). Metals are • ductile, can be shaped into wires • malleable, can be hammered into a flat sheet • good conductors of electricity • melted at much higher temperatures than nonmetals • solids at room temperature, except for mercury (Hg) © 2014 Pearson Education, Inc.

Metals, Nonmetals, and Metalloids Except for aluminum (Al), the elements along the zigzag line are metalloids. Metalloids • include B, Si, Ge, As, Sb, Te, Po, and At • exhibit some properties typical of metals and some typical of nonmetals • are better conductors of heat and electricity than nonmetals, but not as good as metals • are semiconductors because they can be modified to function as conductors or insulators © 2014 Pearson Education, Inc.

Metals, Nonmetals, and Metalloids Nonmetals include elements such as hydrogen (H), carbon (C), nitrogen (N), oxygen (O), chlorine (Cl), and sulfur (S). Nonmetals • not especially shiny, malleable, or ductile, and are often poor conductors of heat and electricity • typically have low melting points and low densities © 2014 Pearson Education, Inc.

Metals, Nonmetals, and Metalloids © 2014 Pearson Education, Inc.

Chemistry Link to Health • Only 20 elements are essential for the well-being and survival of the human body. • Only four elements, oxygen (O), carbon (C), hydrogen (H) and nitrogen (N) make up 96 % of our body mass. • The macrominerals Ca, P, K, Cl, S, Na, and Mg are involved in the formation of bones and teeth, and the maintenance of essential body functions. © 2014 Pearson Education, Inc.

Chemistry Link to Health © 2014 Pearson Education, Inc.

Learning Check Match the elements to the description: A. Metals in Group 4 A (14) (1) Sn, Pb (2) C, Si (3) C, Si, Ge, Sn B. Nonmetals in Group 5 A (15) (1) As, Sb, Bi (2) N, P As, Sb C. (3) N, P, Metalloids in Group 4 A (14) (1) C, Si, Ge (2) Si, Ge (3) Si, Ge, Sn, Pb © 2014 Pearson Education, Inc.