Chapter 3 Atoms and Elements

Chapter 3 Atoms and Elements 3.2The Periodic Table

Groups and Periods On the periodic table • Groupscontain elements with similar properties and are arranged in vertical columns. • Periods are the horizontal rows of elements.

Groups and Periods (continued)

Periodic Table

Group Numbers Group Numbers • Use numbers 1–18 to identify the columns from left to right. • Use the letter A for the representative elements (1A to 8A) and the letter B for the transition elements.

Representative Elements • Several groups of representative elements are known by common names.

Alkali Metals Group 1A(1), the alkali metals, includes lithium, sodium, and potassium.

Halogens Group 7A(17), the halogens,includes chlorine, bromine, and iodine.

Learning Check Identify the element described by the following: A. Group 7A(17), Period 4 1) Br 2) Cl 3) Mn B. Group 2A(2), Period 3 1) beryllium 2) magnesium 3) boron C. Group 5A(15), Period 2 1) phosphorus 2) arsenic 3) nitrogen

Solution A. Group 7A (17), Period 4 1) Br B. Group 2A (2), Period 3 2) magnesium C. Group 5A(15), Period 2 3) nitrogen

Metals, Nonmetals, and Metalloids The heavy zigzag line separates metals and nonmetals. • Metals are located to the left. • Nonmetals are located to the right. • Metalloidsare located along the heavy zigzag line between the metals and nonmetals.

Properties of Metals, Nonmetals, and Metalloids Metals • are shiny and ductile • are good conductors of heat and electricity Nonmetals • are dull, brittle, and poor conductors of heat and electricity • are good insulators Metalloids • are better conductors than nonmetals, but not as good as metals • are used as semiconductors and insulators

Comparing a Metal, Metalloid, and Nonmetal

Learning Check Identify each of the following elements as 1) metal, 2) nonmetal, or 3) metalloid. A. sodium ____ B. chlorine ____ C. silicon ____ D. iron ____ E. carbon ____

Solution Identify each of the following elements as 1) metal, 2) nonmetal, or 3) metalloid. A. sodium 1 metal B. chlorine 2 nonmetal C. silicon 3 metalloid D. iron 1 metal E. carbon 2 nonmetal

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

Chapter 3 Atoms and Elements