structure of atoms chapter 5. you will learn about: structure of atoms isotopes electron arrangement...

Structure of Atoms

Structure of Atoms

Chapter 5

Chapter 5

You will learn about:

• Structure of atoms

• Isotopes

• Electron arrangement in atoms

• The Periodic Table

• Ions

You will learn about:

• Structure of atoms

• Isotopes

• Electron arrangement in atoms

• The Periodic Table

• Ions

contentscontents

ParticleParticle Relative MassRelative Mass Relative Electric ChargeRelative Electric Charge

proton 1 +1

neutron 1 0

electron 1/2000 0 -1

structure of atomsstructure of atoms

three types of particles in an atom: proton, neutron and electron

three types of particles in an atom: proton, neutron and electron

compositioncomposition

consists of a nucleus surrounded by electrons in shells

nucleus in turn contains protons and neutrons

consists of a nucleus surrounded by electrons in shells

nucleus in turn contains protons and neutrons

structure of an atom: structure of an atom:

compositioncomposition


number of protons is the proton number (atomic number) number of electrons = number of protons atom is

electrically neutral total number of protons and neutrons is the nucleon number

(mass number)

number of protons is the proton number (atomic number) number of electrons = number of protons atom is

electrically neutral total number of protons and neutrons is the nucleon number

(mass number)

+ -

structure of an atom

electrons in shells around nucleus

nucleus(protons + neutrons)

-

simplified structure of a typical atom: simplified structure of a typical atom:

simplified structuresimplified structure


structure of a carbon atom

-

+6

6

6

nucleon number= 6 + 6 = 12

proton number= 6

-+

electron

proton

neutron

written in symbol form

symbol tells us that the atom

Cl

symbol formsymbol form


35

17proton number

nucleon number symbol of the

element

o is of element chlorineo has proton number 17 (so it contains 17 protons)o has 17 electrons (number of protons = number of electrons)o has nucleon number 35 (so number of protons + number of

neutrons = 35)o it must contain 35 – 17 = 18 neutrons

1111number of protons

23 - 11 = 12

11

24 – 11 = 13number of neutrons

11number of electrons

IsotopesIsotopes Na Na 2424

1111 Na Na 2323

1111

are atoms of the same element with different numbers of neutrons

same proton number but different nucleon numbers (mass numbers)

are atoms of the same element with different numbers of neutrons

same proton number but different nucleon numbers (mass numbers)

isotopesisotopesisotopesisotopes

have same chemical properties and form compounds with the same formula because they have the same number and arrangement of electrons

have small differences in physical properties

can be radioactive or non-radioactive

have same chemical properties and form compounds with the same formula because they have the same number and arrangement of electrons

have small differences in physical properties

can be radioactive or non-radioactive

isotopesisotopesisotopesisotopes

82 and above

21

Maximum NumberMaximum Number

of Electronsof ElectronsShell NumberShell Number

electron arrangement in atomselectron arrangement in atoms

electrons are arranged around the nucleus of the atom in shells

atomic nucleus (positive charge) attracts the electrons (negative charge) by an electrostatic force

each shell can hold a maximum number of electrons

electrons are arranged around the nucleus of the atom in shells

atomic nucleus (positive charge) attracts the electrons (negative charge) by an electrostatic force

each shell can hold a maximum number of electrons

electronselectrons

electrons always go into the shell nearest to the nucleus, if there is room; otherwise they go to the next available shell

electrons always go into the shell nearest to the nucleus, if there is room; otherwise they go to the next available shell

electronic structure & outer electronselectronic structure & outer electrons


is the arrangement of electrons in atoms

three ways of showing the electronic structure of a silicon atom:

is the arrangement of electrons in atoms

three ways of showing the electronic structure of a silicon atom:

full electronic structure

+ ---

-

-

-

- -

- -

-- + --

outer electronic structure

valency electrons

electronic structure

2.8.42.8.4

-

-

-

-

valence shell


electronic structures of the first 20 elements: electronic structures of the first 20 elements:


2.4426Ccarbon

2.5527Nnitrogen

2.6628Ooxygen

2.7729Ffluorine

2.1123Lilithium

2.2224Beberyllium

2.3325Bboron

44thth shellshell

33rdrd shellshell

22ndnd shellshell

11stst shellshell

2

2

1

Number of Electrons inNumber of Electrons in

8Ne

He

H

SymbolSymbol

10

2

1

Proton Proton NumberNumber

1hydrogen

2.8

2

Simplified Simplified Electronic Electronic StructureStructure

neon

helium

ElementElement


electronic structures of the first 20 elements: electronic structures of the first 20 elements:


2.8.668216Ssulphur

2.8.778217Clchlorine

2.8.888218Arargon

2.8.8.1188219Kpotassium

2.8.338213Alaluminium

2.8.448214Sisilicon

2.8.558215Ophosphorus

44thth shellshell

33rdrd shellshell

22ndnd shellshell

11stst shellshell

2

2

2

Number of Electrons inNumber of Electrons in

8

8

8

Ca

Mg

Na

SymbolSymbol

20

12

11

Proton Proton NumberNumber

8

2

1

2

2.8.1sodium

2.8.8.2

2.8.2

Simplified Simplified Electronic Electronic StructureStructure

calcium

magnesium

ElementElement

arrangement of elements in a table

periods show the elements arranged horizontally in order of proton number (atomic number)

across each period, the number of outer shell electrons increases from 1 to 8

groups show the elements with the same number of outer electrons arranged in vertical columns

arrangement of elements in a table

periods show the elements arranged horizontally in order of proton number (atomic number)

across each period, the number of outer shell electrons increases from 1 to 8

groups show the elements with the same number of outer electrons arranged in vertical columns

the Periodic Tablethe Periodic Table


group number

simplified electronic structure

I II III IV V VI VII

VIII

full electronic structure



proton numbername of element

symbol

ionsions

are charged particles; can be either positively or negatively charged

atoms form ions by gaining or losing electrons to obtain the electronic structure of a noble gas

are charged particles; can be either positively or negatively charged

atoms form ions by gaining or losing electrons to obtain the electronic structure of a noble gas

ionsions

non-metallic

atom takes in electron(s)

Negative IonsNegative Ions

metallictype of atoms

atom loses electron(s)

movement of electrons

Positive IonsPositive Ions

ionsions

a negative ion is formed by gaining electrons to an atom

a positive ion is formed by losing electrons to an atom

a negative ion is formed by gaining electrons to an atom

a positive ion is formed by losing electrons to an atom

ionsions

17

17

CCll atom atom

18

17

CCll-- ion ion

8

8

O atomO atom

10Number of electrons

8No of protons

OO2-2- ion ion

11

11

Na atomNa atom

10

11

NaNa++ ion ion

12

12

Mg atomMg atom

10Number of electrons

12No of protons

MgMg2+2+ ion ion

Proton Proton numbernumber

NeutronsNeutrons

ProtonsProtons

Positive Positive ionsions

Negative Negative ionsions

ElectronsElectrons

Nucleon Nucleon numbernumber

IsotopesIsotopes

Periodic Periodic TableTable

lose electrons lose electrons to becometo become

gain electrons gain electrons to becometo become

containcontain

havehave

shellsshellsmembers have members have

same number of same number of electrons in electrons in

which give out which give out radiation areradiation are

negative negative chargecharge

areare

is the sum ofis the sum of

containcontain

containcontain

are arranged in

are arranged in

outer outer shellshell

furthest from furthest from nucleus isnucleus is

electron electron arrangement isarrangement is

electronic electronic structurestructure

groupgroup

vertical vertical column iscolumn is

havehave

positive positive chargecharge

have different have different numbers ofnumbers of

radioactiveradioactive neutralneutral

containcontain

containcontain

nucleusnucleus

elements in elements in order oforder of

is the sum ofis the sum of

AtomsAtoms

structure of atoms chapter 5. you will learn about: structure of atoms isotopes electron arrangement...

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