It's Elemental

Its Elemental

Table of Contents

It's Elemental

What is an Atom? Diagram of an Atom Sizing Up Atoms

Discovering the Periodic Table Periodic Table of Elements How to Read the Periodic Table Discovering the Atom

Metals & Non-Metals Quiz: Name That Element * Molecules & Compounds

Physical Changes & Chemical Changes Atom Structures

Flash Cards: Memorize the Periodic Table Periodic Table of Elements: Blank

Certificate of Completion Answer Sheets

* Has an Answer Sheet

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(What is an Atom?)

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People were thinking about atoms as early as 370 B.C.! A philosopher named Democritus believed that there must be an unbreakable particle that makes up all things. Not everyone agreed with him.

The word atom comes from the Greek word atomos, which means indivisible. This was the name Democritus gave to his theoretical particle.

In the 1800s scientists knew that there were certain substances, which we now call elements, that cannot be broken down into anything simpler.

Then, a scientist named John Dalton discovered that all elements are made up of tiny particles called at- oms.

As it turns out, atoms can also be broken down into smaller pieces. However, if you divide an atom of hy- drogen, it wont be hydrogen any more.

This means that an atom is the smallest particle of a substance that has the same qualities of that sub- stance.

Atoms are also made up of even smaller particles. Theseareknownassub-atomicparticles,or protons, neutrons and electrons.

Painting of Democritus

Painting of John Dalton

(Diagram of an Atom)

Protons : have a positive electrical charge. Electrons : have a negative electrical charge. Neutrons : are neutral.

Nucleus : is at the center of the atom. It is where the protons and neutrons are. The electrons swirl around the nucleus. Most of the atoms mass is in the nucleus.

Diagram of a Helium Atom

protons

neutrons

electrons

nucleus

Protons and electrons are attracted to each other, but protons repel protons and electrons repel electrons. All atoms have an equal number of protons and electrons. If an atom loses or gains an electron, then it becomes an ion. An ion is an electri- cally charged atom.

(Try This)

1. Get a balloon and rub it on your hair or clothes. The electrons from your hair or clothes will attach to the balloon and give it a negative (-) charge.

2. When the balloon is near the water the electrons on the negatively charged bal- loon move away from it. What is left is a positive(+) area of water near the balloon.

3. The positively-charged area of water and the negatively-charged balloon attract!

(-)

(+)

(Sizing Up Atoms)

An atom is so small that

along the width of your hair.

If an electron weighed the same as a dime, a proton would weigh the same as a gallon of milk!

its electrons would be a foot-

electron

(Discovering the Periodic Table)

By the late 1800s scientists had discovered

and named most of the elements, but they did not understand the elements or their behavior. An important discovery by Russian chemist Dmitri Mendeleev showed that when you arrange the elements in rows and columns you can see the similarities between them. His discovery proved that the elements repeat certain characteristics at regular intervals, or periodically.

Example: look at the far left column of the table. Lithium, sodium and potassium line up vertically, and they are all very similar metals. They are soft, low

in density and solid at room temperature. They also have very similar reactions with other substances.

Photograph of Dmitri Mendeleev

(36.941LiLithium1122.98977NaSodium1939.0983KPotassium)+

(Non-MetalsMetalloids) (Noble Gases) (Halogens)Periodic Table of Elements

(11.00794HHydrogen) (Alkali Metals) (Alkaline Earth Metals) (Transition Metals)Atomic Number Atomic Mass

(Lanthanides)Symbol Name

1

1.00794

H

Hydrogen

3

6.941

Li

Lithium

11

22.98977

Na

Sodium

4

9.012182

Be

Beryllium

12

24.3050

Mg

Magnesium

Actinides

5

10.811

B

Boron

13

26.98154

Al

Aluminum

6

12.0107

C

Carbon

14

28.0855

Si

Silicon

7

14.0067

N

Nitrogen

15

30.97376

P

Phosphorus

8

15.9994

O

Oxygen

16

32.065

S

Sulfur

9

18.99840

F

Flourine

17

35.453

Cl

Chlorine

2

4.002602

He

Helium

10

20.1797

Ne

Neon

18

39.948

Ar

Argon

19

39.0983

K

Potassium

37

85.4678

Rb

Rubidium

55

20

40.078

Ca

Calcium

38

87.62

Sr

Strontium

56

21

44.9559

Sc

Scandium

39

88.9059

Y

Yttrium

71

22

47.867

Ti

Titanium

40

91.224

Zr

Zirconium

72

23

50.9415

V

Vanadium

41

92.9064

Nb

Niobium

73

24

51.9961

Cr

Chromium

42

95.96

Mo

Molybdenum

74

25

54.938

Mn

Manganese

43

(97.9072)

Tc

Technetium

75

26

55.845

Fe

Iron

44

101.07

Ru

Ruthenium

76

27

58.9332

Co

Cobalt

45

102.9055

Rh

Scandium

77

28

58.6934

Ni

Nickel

46

106.42

Pd

Palladium

78

29

63.546

Cu

Copper

47

107.8682

Ag

Silver

79

30

65.38

Zn

Zinc

48

112.411

Cd

Cadmium

80

31

69.723

Ga

Gallium

49

114.818

In

Indium

81

32

72.64

Ge

Germanium

50

118.710

Sn

Tin

82

33

74.9216

As

Arsenic

51

121.760

Sb

Antimony

83

34

78.96

Se

Selenium

52

127.60

Te

Tellurium

84

35

79.904

Br

Bromine

53

126.9045

I

Iodine

85

36

83.798

K

Krypton

54

131.293

Xe

Xenon

86

132.9055

137.327

174.9668

178.49

180.9479

183.84

186.207

190.23

192.217

195.084

196.9666

200.59

204.3833

207.2

209.9804 (208.982) (209.987) 222.0176

Cs

Caesium

87

(223)

Fr

Ba

Barium

88

(226)

Ra

Lu

Lutetium

103

(262)

Lr

Hf

Hafnium

104

(261)

Rf

Ta

Tantalum

105

(262)

Db

W

Tungsten

106

(266)

Sg

Re

Rhenium

107

(264)

Bh

Os

Osmium

108

(277)

Hs

Ir

Iridium

109

(268)

Mt

Pt

Platinum

110

(271)

Ds

Au

Gold

111

(272)

Rg

Hg

Mercury

112

(285)

Cp

Tl

Thallium

113

(284)

Uut

Pb

Lead

114

(289)

Fl

Bi

Bismuth

115

(288)

Uup

Po

Polonium

At

Astatine

Rn

Radon

(Copyright 2012-2013 Education.com www.education.com/worksheets)Francium

Radium

Lawrencium

Rutherfordium

Dubnium

Seaborgium

Bohrium

Hassium

Meitnerium

Darmstadtium Roentgenium

Copernicum

Ununtrium

Flerovium

Ununpentium

57

138.9055

La

58

140.116

Ce

59

140.9077

Pr

60

144.242

Nd

61

(145)

Pm

62

150.36

Sm

63

151.964

Eu

64

157.25

Gd

65

158.9254

Tb

66

162.5

Dy

67

164.9303

Ho

68

167.259

Er

69

168.9342

Tm

70

173.054

Yb

Lanthanum

Cerium

Praseodymium Neodymium

Promethium

Samarium

Europium

Gadolinium

Terbium

Dysprosium

Holmium

Erbium

Thulium

Ytterbium

89