Chapter 3 Atoms and Elements

Home , Boron, Group (periodic table), Metal, Metalloid, Nonmetal, Period (periodic table)

1 Groups and Periods

On the periodic table • Elements are arranged according to similar properties • Groups contain elements with similar properties in vertical columns • Periods are horizontal rows of elements

2 Groups and Periods

3 Periodic Table

4 Group Numbers

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

5 Names of Some Representative Elements

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

6 Alkali Metals

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

7 Halogens

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

8 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

9 Solution

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

10 Metals, Nonmetals, and Metalloids

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

11 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 • Are good insulators Metalloids • Are better conductors than nonmetals, but not as good as metals • Are used as semiconductors and insulators

12 Comparing a Metal, Metalloid, and Nonmetal

13 Learning Check

Identify each of the following elements as: 1) metal 2) nonmetal 3) metalloid

A. sodium ____ B. chlorine ____ C. silicon ____ D. iron ____ E. carbon ____

14 Solution

Identify each of the following elements as: 1) metal 2) nonmetal 3) metalloid

A. sodium metal B. chlorine nonmetal C. silicon metalloid D. iron metal E. carbon nonmetal

15 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

16 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