Mrs TeoccThe Chinese High SchoolDiagrams by Ms Angela Ng

The Structure of Atoms

&

Formation of Ions

Revision

An Atom consists of

electrons

protons

neutrons

Electronic Structure of Sodium

nucleus

He Ne Ar

The Electronic Structure of Noble GasesThe Electronic Structure of Noble Gases

Noble gasesNoble gases

- - very very stablestable electron arrangement electron arrangement

- do not - do not gaingain or or loselose electrons electrons => unreactive => unreactive

The Electronic Structure of Noble The Electronic Structure of Noble GasesGases

X

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

X

Other atoms try to become likethose Other atoms try to become likethose of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

X

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

X

Gain of Gain of electronelectronGain of Gain of electronelectron

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Y

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Y

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Y

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Y

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Y

Loss of electronLoss of electron

Other atoms try to become like those Other atoms try to become like those of noble gasesof noble gases => => gaingain or or loselose electrons and form electrons and form chemical bonds with other atoms chemical bonds with other atoms to to attain octet or duplet configuration attain octet or duplet configuration

Formation of Ions

1. In an atom, the number of 1. In an atom, the number of protons protons is equal to the number of is equal to the number of

electrons.electrons. => electrically neutral

2. If electrons are added or removed,

it becomes a charged particle => ion

Cl atomCl atom

17p 18nNo overall No overall

chargecharge

p=17p=17

e=17e=17

To become negative ions (anions)To become negative ions (anions)

To become negative ions (anions)To become negative ions (anions)

17p 18n

To become negative ions (anions)To become negative ions (anions)

17p 18n

To become negative ions (anions)To become negative ions (anions)

17p 18n

To become negative ions (anions)To become negative ions (anions)

17p 18n

Gain of Gain of a a

electronelectron

To become negative ions (anions)To become negative ions (anions)

17p 18n

More More electronelectrons than s than

protonsprotons

To become negative ions (anions)To become negative ions (anions)

17p 18n

has has overall overall

negative negative chargecharge

Negative Negative ion ion (anion)(anion)

ClCl--

Due to addition of 1 electron

To become negative ions (anions)To become negative ions (anions)

17p 18n

O atomO atom

8p8nNo overall No overall

chargecharge

p=8p=8

e=8e=8

To become negative ions (anions)To become negative ions (anions)

To become negative ions (anions)To become negative ions (anions)

8p8n

To become negative ions (anions)To become negative ions (anions)

8p8n

To become negative ions (anions)To become negative ions (anions)

8p8n

To become negative ions (anions)To become negative ions (anions)

8p8n

Adding Adding of 2 of 2

electronelectronss

To become negative ions (anions)To become negative ions (anions)

8p8n

More More electronelectrons than s than

protonsprotons

To become negative ions (anions)To become negative ions (anions)

8p8n

has overall has overall negative negative chargecharge

negative negative ion ion (anion)(anion)

OO22--

Due to addition of 2 electrons

2-

To become negative ions (anions)To become negative ions (anions)

8p8n

-> e.g. -> e.g. ClCl--, O, O2-2-

Generally non-metals have many outer electrons (4-7)They

-> -> tend to ______ electronsgain

-> form negative ions (anions)

Na atomNa atom

11p12nNo overall No overall

chargecharge

p=11p=11

e=11e=11

To become positive ions (cations)To become positive ions (cations)

To become positive ions (cations)To become positive ions (cations)

11p12n

To become positive ions (cations)To become positive ions (cations)

11p12n

Removal Removal of 1 of 1

electronelectron

To become positive ions (cations)To become positive ions (cations)

11p12n

More More protons protons

than than electronelectron

ss

To become positive ions (cations)To become positive ions (cations)

11p12n

has overall has overall positive positive chargecharge

positive positive ion ion (cation)(cation)NaNa

++

+

Loss of 1 electron

To become positive ions (cations)To become positive ions (cations)

11p12n

Mg atomMg atom

No overall No overall chargecharge

To become positive ions (cations)To become positive ions (cations)

12p12n

To become positive ions (cations)To become positive ions (cations)

12p12n

To become positive ions (cations)To become positive ions (cations)

12p12n

To become positive ions (cations)To become positive ions (cations)

12p12n

To become positive ions (cations)To become positive ions (cations)

12p12n

Removal Removal of 2 of 2

electronelectronss

To become positive ions (cations)To become positive ions (cations)

12p12n

More More protons protons

than than electronelectron

ss

To become positive ions (cations)To become positive ions (cations)

12p12n

has overall has overall positive positive chargecharge

MgMg2+2+

Loss of 2 electrons

positive positive ion ion (cation)(cation)

To become positive ions (cations)To become positive ions (cations)

12p12n

2+

->-> form positive ions (cations) form positive ions (cations)

-> -> example Naexample Na++, Mg, Mg2+2+

Generally metalsmetals have few outer electrons (1-3 electrons)

They

->-> tend to _________electronslose