ATOMIC STRUCTUR

E

ATOMIC STRUCTURE1. Rutherford’s Experiment2. Basic Particles of Atom3. Atomic Number and Mass Number4. Isotope, Isobar, Isotone, and

Isoelectron5. Electron Configuration and

Valence Electron6. Development of Atomic Theory

1. RUTHERFORD’S EXPERIMENTCONCLUSION: The atom consist of

nucleus which has positive charge and the mass of atom is centered in the nucleus

There are many electrons which move around nucleus outside the nucleus and the amount of electrons equal to the charge of nucleus, so the atom has neutral characteristic

CONCLUSION: The atom consist of nucleus which has positive charge and

the mass of atom is centered in the nucleus There are many electrons which move around nucleus

outside the nucleus and the amount of electrons equal to the charge of nucleus, so the atom has neutral characteristic

radium

Plumbum plate

ray

gold

Detector (ZnS)

1. RUTHERFORD’S EXPERIMENT

2. Basic Particles of Atom

ATOM

ELECTRON

NEUTRON

NUCLEUS

PROTON

3. Atomic Number and Mass Number

Explanation:X : symbol of atomA : mass number, shows the amount of proton + neutronZ : atomic number, shows the

amount of proton/electron

XAZ

EXERCISEComplete the table below!

Atomic Number

Mass Number

Proton Neutron Electron Symbol

Ne181010 1081018Ag108

4747 476147108

28

1626

56

83

50

59

31

56

137

209

119

28

16

26

56

83

50

31

1530

81

126

69

28

16

26

56

83

50

Ni5928

S3116

Fe5626

Ba13756

Bi20983

Sn11950

IONIC REACTION EQUATION

Na2311 + e

e = 11

p = 11

n = 12

Na2311

Cl3517

Cl3517+ e

e = 17

p = 17

n = 18

e = 10

p = 11

n = 12

e = 18

p = 17

n = 18

POSITIVE ION (KATION) Be9

429

4Be + 2e

e = 2

p = 4

n = 5

e = 4

p = 4

n = 5

P3115 + 3e331

15P

e = 15

p = 15

n = 16

e = 18

p = 15

n = 16

NEGATIVE ION (ANION)

EXERCISEComplete the table below!

Atom Number

Mass Number

Proton Neutron Electron Symbol

K3919

2168O

32713Al

Br8035

19 18201939

8

13

35

16

27

80 35

13

8 8

14

45

10

10

36

4.ISOTOPEISOBAR

ISOTONE ISOELECTRON

ISOTOPEDEFINITION OF ISOTOPE:

The atoms which have similar atomic number but the mass number is different.

EXAMPLE:

Cl3517 Cl37

17and

C126 C136 C146and,

ISOBARDEFINITION OF ISOBAR:

The atoms which have different atomic number (the element is different) but the mass number is same.

EXAMPLE:

N147 C146and

Na2411 Mg24

12and

ISOTONEDEFINITION OF ISOTONE:

The atoms which come from different element, but the amount of neutron is same

EXAMPLE:

P3115 S3216and

Ca4020 K3919and

ISOELECTRONDEFINITION OF ISOELECTRON:

The atoms which come from different element, but the amount of electron is same

EXAMPLE:

32713Al Ne20

10and, -2168O

p = 13

n = 14

e = 10

p = 8

n = 8

e = 10

p = 10

n = 10

e = 10

5. 5. Electron Electron

Configuration Configuration and and

Valence ElectronValence Electron

ELECTRON ELECTRON CONFIGURATIONCONFIGURATION

An electron configuration is the spreading of the electron An electron configuration is the spreading of the electron in shells of an atom. The configuration must follow the in shells of an atom. The configuration must follow the regulations below:regulations below:

• The maximum quantity of electron in the shell is The maximum quantity of electron in the shell is 2n2n22

n Value of K shell = 1, so, the max. quantity of electron =n Value of K shell = 1, so, the max. quantity of electron =n Value of L shell = 2, so, the max. quantity of electron =n Value of L shell = 2, so, the max. quantity of electron =n Value of M shell = 3, so, the max. quantity of electron =n Value of M shell = 3, so, the max. quantity of electron =etcetc..

• The maximum quantity of electrons in the external shell The maximum quantity of electrons in the external shell is is 88

• Normally, the filling of electrons starts at the inner shell Normally, the filling of electrons starts at the inner shell (K). Elements with atom number 1 to 18, is filled with (K). Elements with atom number 1 to 18, is filled with electrons in their external shell only if the inner shell is electrons in their external shell only if the inner shell is full.full.

• The elements with atomic number more than 18, the The elements with atomic number more than 18, the external shell, which is the fourth shell (N) and other external shell, which is the fourth shell (N) and other shell levels, can be filled with electrons, evenshell levels, can be filled with electrons, even though the though the third shell (M) has not full yet.third shell (M) has not full yet.

2818

EXERCISEEXERCISECOMPLETE THE TABLE BELOW!COMPLETE THE TABLE BELOW!

AtomAtomElectron SkinElectron Skin

KK LL MM NN OO PP QQ

33LiLi

1212MgMg

3131GaGa

5050SnSn

3333AsAs

5252TeTe

3535BrBr

8686RnRn

2

2

2

2

2

2

2

2

1

8

8

8

8

8

8

8

2

3

18 18 4

18 5

18 18 6

18 7

18 32 18 8

18

VALENCE ELECTRONVALENCE ELECTRON Valence electron is the quantity of electron on the Valence electron is the quantity of electron on the

external shell of which the maximum quantity is 8.external shell of which the maximum quantity is 8.Example:Example:

1.1. 1111 Na Na

Electron configuration: 2 8 1Electron configuration: 2 8 1Quantity of valence electron: Quantity of valence electron: 11

2.2. 2020 Ca Ca

Electron configuration: 2 8 8 2Electron configuration: 2 8 8 2Quantity of valence electron: Quantity of valence electron: 22

3.3. 5454 Xe Xe

Electron configuration: 2 8 18 18 8Electron configuration: 2 8 18 18 8Quantity of valence electron: Quantity of valence electron: 88

6. Development of Atomic Theory Atomic theory of Dalton Atomic theory of J.J.

Thomson Atomic theory of Rutherford Atomic theory of Niels Bohr Modern atom theory

ATOMIC THEORY OF DALTON

• A substance consist of minute particles that can’t be divided, and this is called an atom with a small massive ball shape

• Atoms of an element are identical but they are different from atoms of the other elements

• Chemically, atoms are interwoven to each other to perform a molecule with a simple comparison

• A compound is the product of the reaction of atom

• An atom of an element is permanent, can’t de divided or created or destroyed

Atom model of Dalton

ATOM THEORY OF J.J. THOMSON

Negative charged electrons spread

inside the positive charged ball (looks

like the currants that spread over a piece

of cake, so, its called COOKIE THEORY)

Atom model of J.J. Thomson

electron

Cloud of proton

--

-

--

ATOM THEORY OF RUTHERFORD All of positive charge and most of atom

mass are concentrated at a particle at the center of the atom. This particle is the nucleus of an atom.

Some light electrons that can’t restrained the high speed of alpha particles go around the nucleus like planets that orbit to the sun.

An atom is neutral, meaning that in an atom, the charge of the electrons (negative) is equal with the charge of the nucleus (positive)

Unfortunately Rutherford can’t explain, why an electron can’t attach

to the nucleus. Each of them have different charges, an electrons will

attach to the nucleus in a spiral orbit track and then hits the nucleus.

Atom model of

Rutherford

+

-

Skin of atom

electron

Atom radius

nucleus

ATOM THEORY OF NIELS BOHR

1.An atom consist of a nucleus (positive) that is surrounded by electrons (negative)

2. An electron goes around the nucleus in a given orbit known as stationary

energy. This is called the major energy level or the major quantum number.

3. If an electron stays on its stationary energy level, there will be no ray

sparks.4. An electron can move to the upper level if it absorbs an energy, and an

electron can move to the lower level if it releases some of its energy.

THAT’S ALL

Periodic table of elements-2