topic 3 atomic structure

7/21/2019 Topic 3 Atomic Structure

http://slidepdf.com/reader/full/topic-3-atomic-structure 1/40



Learning Outcomes

By the end of this topic, you should be able to:

Explain the history of atomic model;

Describe subatomic particles;

Differentiate between atomic number, nucleon number and

mass number;

Summarise the concepts of isotopes;

Show how to configure the electronic configuration of

atom; and

Summarise the concept of valence electrons.



3.1 HISTORY OF ATOMIC MODEL



F!DAME!TAL "ARTICLES

According to the atomic theory, matter is made

up of much smaller particles known as atoms.

Atoms consist principally of three fundamentalparticles electrons, protons, and neutrons.

!oth the protons and neutrons reside in the

nucleus and they are called nuc#eon.

Electrons reside in orbits around the nucleus.



Structure o$ t%e atom



3.3 "ROTO! !M'ER A!D

!CLEO! !M'ER



Atomic num&er ( "roton num&er

"he number of protons in the nucleus of an atom

determines the atomic number #$% and indicates

the element&s identity.




'or a neutral atom, the atomic number alsodescribes the number of electrons around thenucleus.




(n the periodic table, elements are arranged in

order of increasing atomic numbers.




"he atomic number of an element is the identity

of the element.

"he number of proton in the nucleus of every atom in anelement is always the same.



Mass num&er ( !uc#eon num&er

"he nucleon number of an element is the total

number of protons and neutrons in the nucleus

of an atom.



!uc#i)e S*m&o#

"he composition of a nucleus is indicated by its

nuc#i)e s*m&o#.



!uc#eon an) proton num&ers o$ an

e#ement



3.+ ISOTO"ES

Isotopes ) atoms of the same element that

have different masses.

"he isotopes of a particular element all have thesame num&er o$ protons but )i$$erent

num&ers o$ neutrons.



Isotope "rotons E#ectrons !eutrons !uc#eus

*ydrogen+

#protium% -

*ydrogen+

#deuterium%

*ydrogen+/#tritium%

Isotopes o$ H*)rogen



Isotopes o$ H*)rogen



Isotopes o$ Some E#ements

0age 12 #3odule%



Isotopes



0ut the mass number #nucleon number% afterthe name of the element. carbon+

carbon +4 uranium+/2

!aming Isotopes



'ind the number of protons

number of neutrons

number of electrons

Atomic number

3ass number

5ame

Cl35

17

E,amp#e +-1




number of neutrons

number of electrons

Atomic number

3ass number

5ame

Cl37

17

E,amp#e +-1




number of neutrons

number of electrons

Atomic number

3ass number

5ame

Cu63

29

E,amp#e +-1




number of neutrons

number of electrons

Atomic number

3ass number

5ame

Cu65

29

E,amp#e +-1



E,ercise

(f an element has an atomic number of /4

and a mass number of 67 what is the number of protons

number of neutrons

number of electrons

nuclide symbol

name



E,ercise

(f an element has 8 protons and 4-

neutrons what is the Atomic number

3ass number

5umber of electrons

5uclide symbol

5ame



E,ercise

(f an element has 67 electrons and 6

neutrons what is the Atomic number

3ass number

5umber of protons

5uclide symbol

5ame



Speci$ic Isotopes an) t%eir

sages



5uclear 0ower Stations

5uclear fission is the type of reaction carried out innuclear reactors.

SES OF ISOTO"ES



(n nuclear reactors the heat generated by the reaction is

used to produce steam that turns a turbine connected to a

generator.

SES OF ISOTO"ES



Food IrradiationFood Irradiation

'ood can be irradiated with γ rays from 1-9o or /69s.

"he benefits of food irradiation are obvious ) it reduces

energy demand by eliminating the need for refrigeration,

and it prolongs the shelf life of various foods.

SES OF ISOTO"ES



Dosage Effect

:p to -- kilorad

(nhibits sprouting of potatoes, onions, garlics. (nactivatestrichinae in pork. ills or prevents insects from reproducing

in grains, fruits, and vegetables.

-- ) --- kiloradsDelays spoilage of meat poultry and fish. <educessalmonella. Extends shelf life of some fruit.

--- to -,--- kiloradsSterili=es meat, poultry and fish. ills insects andmicroorganisms in spices and seasoning.

'ood (rradiation'ood (rradiation

> Strawberries irradiated at --

kilorads #right% are still fresh after

2 days? storage at 4@9; those

not irradiated are moldy.



3. ELECTRO!IC

CO!FI/RATIO! OF ATOMS

"he electron configuration of potassium

.7.7.



Dot an) cross )iagram

"he electron configuration of nitrogen .2



3.0 ALE!CE ELECTRO!S

Balence electrons are the electrons found in the

outermost shell of an atom.



3.0 ALE!CE ELECTRO!S

topic 3 atomic structure

Documents