2.7 an introduction to the periodic table

2.7 An Introduction to the Periodic

Table

Copyright © Houghton Mifflin Company. All rights reserved. 2–2

Periodic TableDmitri Mendeleev (1834-1907)

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings


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.


Groups and Periods



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.


Names of Some 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.



Identify the element described by the following.

A. Group 7A(17), Period 41) Br 2) Cl 3) Mn

B. Group 2A(2), Period 31) beryllium 2) boron 3) magnesium

C. Group 5A(15), Period 21) phosphorus 2) arsenic 3) nitrogen

Learning Check


A. Group 7A (17), Period 41) Br

B. Group 2A (2), Period 33) magnesium

C. Group 5A(15), Period 2

3) nitrogen

Solution


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.



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.

Properties of Metals, Nonmetals, and Metalloids


Comparing a Metal, Metalloid, and Nonmetal


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

A. sodium ____B. chlorine ____C. silicon ____D. iron ____E. carbon ____

Learning Check


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

A. sodium 1 metalB. chlorine 2 nonmetalC. silicon 3 metalloidD. iron 1 metal E. carbon 2 nonmetal

Solution


Metals Tend to Lose Electrons


Nonmetals Tend to Gain Electrons

2.7 an introduction to the periodic table

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