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.

created the periodic table arranged elements by increasing atomic mass 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

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

Periods and Groups

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

Group Numbers

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

Representative Elements Group 1A (1) Group 7A (17) Alkali metals Halogens Chlorine 1Cl22, bromine 1Br22, and iodine 1l22 are halogens from Group 7A 1172. Lithium 1Li2, sodium 1Na2, and potassium 1K2 are some alkali metals from Group 1A 112.

Metals, Nonmetals, and Metalloids The heavy zigzag line on the periodic table separates the metals from nonmetals. Metalloids border the zigzag line.

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)

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

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

Metals, Nonmetals, and Metalloids

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.

Chemistry Link to Health

Chemistry Link to Health

Chemistry Link to Health

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

Solution Match the elements to the description: A. Metals in Group 4A (14) (1) Sn, Pb B. Nonmetals in Group 5A (15) (2) N, P C. Metalloids in Group 4A (14) (2) Si, Ge