ch1.2 periodic table lesson material

8/17/2019 Ch1.2 Periodic Table Lesson Material

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1.2 Formation of Ions

1.3 Periodic Table


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Recall from Previous Lesson


3/27

Refer to page 9 of your notes

Formation of Ions

1. During chemical reactions, some atoms

mightlose/gain

electron(s).

2. Atom becomes an ion (charged particle)when it gains or loses electron(s).


4/27

Question: Why does an atom become a charged particle when it gains

or loses electron(s)?

• An atom is electrically neutral because number of

electrons = number of protons (equal positive an negative

charges).

•!hen it gains or loses electron(s), the positive an

negative charges are not balanced.

•"herefore, the atom becomes a charged particle.

(positivel# charge or negativel# charge)



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Formation of Cations

!hen an atom loses one or more electrons, it becomes a positively charged

particle called cation.

Lithium atom (Li)

3 electrons

3 protons

Net charge: 0

Lithium ion (Li+)2 electrons

3 protons

Net charge: +1


6/27

$n a lithium atom, there are % protons an % electrons.

$n a lithium ion, there are 3 protons and 2 electrons.

"herefore, the lithium ion carries an overall positive charge of 1& an is

written as Li+.

etal Chemical!ymbol "roton#umber $lectronicConfiguration %ain/Lose$lectrons #ame of Ion Formulaof Ion

'oium a 11 (2,,1) *ose 1 electron 'oium ion a&

+agnesium +g 12 (2,,2) *ose 2 electrons +agnesium ion +g2&

Aluminum Al 1% (2,,%) *ose % electrons Aluminum ion Al%&

Metals form positively charged ions (cations).

ore e&amples of Ions of some etals



7/27


Formation of 'nions

!hen an atom gains one or more electrons, it becomes a negatively charged

particle called anion

Fluorine atom (F)

9 electrons

9 protons

Net charge: 0

Fluoride ion (F-)

10 electrons

9 protons

Net charge: -1


8/27


$n a fluorine atom, there are protons an electrons.

$n a fluorie ion, there are protons and * electrons.

"herefore, the fluorie ion carries an overall positive charge of 1- an is

written as F,.

Non-metals form negatively charged ions (anions).

etal Chemical

!ymbol

"roton

#umber

$lectronic

Configuration

%ain/Lose

$lectrons

#ame of Ion Formula

of Ion

hlorine l 1/ (2,,/) 0ain 1 electron hlorie ion l-

#gen (2,3) 0ain 2 electrons ie ion 2-

'ulphur ' 13 (2,,3) 0ain2 electrons 'ulphie ion '2-

ore $&amples of Ions of some #on,metals


9/27

T!in"ing Time #page 1$

!h# o atoms become ions4

(ote5 this will be covere uner chemical boning)

•"o obtain a full valence shell (base on observation

from above eample).

•"o obtain the same electronic structure of a noble gas

so as to be stable


10/27


-ecall. An element is a pure substance that cannot be split

up into two or more simpler substances.

istory of the "eriodic 0able

During the 1th centur#, several chemists loo6e

for patterns in the properties of elements.

"he most successful of these approaches was b#

the 7ussian chemist Dmitri +eneleev in 13.

+eneleev arrange all the 6nown elements in order of their relative atomic

masses.

8e also arrange the elements in hori9ontal rows so that elements with similar

properties were in the same vertical column.


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8e left gaps in his table so that similar elements were in the same vertical

group. "hree of these gaps are shown as asteris6s in the figure above.


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1. 8e preicte the properties of the missing elements from

the properties of elements above an below them in his

table.

2. !ithin 1: #ears of his preictions, the missing elements

had been discovered. "he# were calle scanium,

gallium an germanium.

%. "heir properties were ver# similar to +eneleev;s

preictions.


13/27

Refer to page 12 of your notes "he names of elements arerepresente b# chemical s#mbols.

an chlorine is

represente b# l>.

?lements that are arrange in the same hori9ontal row

belong to the same period. (same number of electrons

shells)

?ach element in a perio has a proton number which is one

less than the element after it. As, we move grauall# from left to right, the properties of the

elements grauall# change from metals to non-metals.

?lements that are arrange in the same vertical column

belong to the same group. ?lements in the same group

have the same chemical properties. "here are groups

of elements from 0roup $ to 0roup @.

Divies metal from non-

metals. ?lements foun

along this line are 6nown as

metallois. "he# have some

properties of metals an

non-metals.


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15/27


%roup number %roup

$ Al6ali metals

$$ Al6aline earth metals

$$ 8alogens

@ oble gases

(a) %roup

"he groups in the Berioic "able are numbere from I to 1II an then%roup .

'ome of these groups have names5

1. ?lements between 0roup $$ an $$$ are 6nown as transition metals ortransition elements.

2. ?lements in the same group have similar chemical properties an

will unergo the same t#pe of chemical reactions.


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(b) "eriod

?ach perio is numbere, 1, 2, %, etc.

?lements in the *st

period will onl# have their *st

shell fully/partiallyoccupied with electrons.

?lements in the 2nd period will have their *st shell fully occupied with

electrons, an their 2nd shell fully/partially occupied with electrons.


17/27

Refer to page 1% of your notes

Element Protonnumber

Number of electrons in Electronicconfiguration

Period Group 1st shell 2nd shell 3rd shell

th shell

H1 1 1 1 -

He2 2 2 1 0

Li3 2

121 2 !

"e# 2

222 2 !!

"

$ 2

3

23 2 !!!%

& 2#

2# 2 !' N

2$

2$ 2 '

* 2&

2& 2 '!F

9 2

2 2 '!!

Ne 10 2 * 2* 2 0 Na

11 2* 1

2*1 3 !g

12 2* 2

2*2 3 !!,l

13 2* 3

2*3 3 !!!i

1# 2* #

2*# 3 !'

. 1$ 2 * $ 2*$ 3 '


18/27

Refer to supplementary notes

%roup * $lements 'lali etals

1. "he elements in 0roup 1 are 6nown as

al6ali metals because the# react with

water to form al6alis.

2. "he# are reactive metals an arestore in oil to prevent them fromreacting with water an air.

Electronic Structure1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own these groups these increases5Physical Property1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own these groups these increases5Chemical Properties1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own these groups these increases51) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own these groups these increases5


19/27

Electronic Structure1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own, these groups these increases5Physical Property1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own, these groups these increases5Chemical Properties1) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own, these groups these increases51) ne ?lectron on the outer most shell1) All al6ali metals react with col water to form h#rogen an an al6alin going own, these groups these increases5

%roup I


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%roup 1II $lements alogens

"he elements in 0roup $$ of the

perioic table are calle

halogens.

"he# form a group of reactive

non,metals.


Electronic Structure1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle haliesn going own these groups5Physical Property1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle haliesn going own these groups5Chemical Properties1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle haliesn going own these groups51) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle haliesn going own these groups5


21/27

Electronic Structure1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle halies.n going own, these groups5Physical Property1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle halies.n going own, these groups5Chemical Properties1) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle halies.n going own, these groups51) 'even ?lectron on the outer most shell1) All halogens react with iron an with other metals to form salts calle halies.n going own, these groups5

%roup 1II


22/27

%roup $lements #oble %ases

1. "he elements in 0roup @ or 0roup $$$

are calle noble gases or inert gases.

2. "he# are the least reactiveelements in the Berioic "able.

%. Apart from helium which has 2

valence electrons, the other noble

gases have valence electrons.

C. "heir full electronic structures maethem unreactive.



23/27

%roup $lements #oble %ases

+ost of the noble gases can be obtaine commerciall# through

fractional istillation of liquefie air.

"roperties of the #oble %ases.

1) +onatomic elements (single atom)

2) olourless gas at room temperature

%) *ow melting point an boiling point that increase on going own

the group

C) $nsoluble in water

:) nreactive E "he# o not react to form compouns.



24/27


(c) "atterns in the "eriodic 0able

ne useful wa# of classif#ing elements is as metals and non,metals.


25/27


(c) "atterns in the "eriodic 0able

nfortunatel#, it is not eas# to classif# some elements in this wa#.

"a6e, for eample, graphite an silicon.

"hese two elements have high melting points an high boiling points

(li6e metals) but the# have low ensities (li6e non-metals).


26/27


"he graphite nose cone of a space

shuttle being teste in a furnace.

!h# is graphite use for the nose cone4

"he nose cone is require to

4ithstand the high temperatureencountere uring atmospheric entr#

an maintain the structure of the

spacecraft,

"g *55

"he# conduct electricity better than non-metals but not as well as metals.?lements with some properties li6e metals an other properties li6e non-

metals are calle metalloids.Fecause of this ifficult# in classif#ing elements neatl# as metals an non-

metals, chemists loo6e for patterns in the properties and reactions of

smaller groups of elements.


27/27

Refer to page 1& of your notes

(d) Charges on ions

harges on the ions forme are relate to the group number an number of

valence electrons

?lements on the left sie of the Berioic "able lose their valence electrons toform cations with charges corresponing to their group number.

?lements on the right sie of the Berioic "able gain electrons to form anions.

"he charges on the anions corresponing to the number of electrons gaine to fill

their valence shells with eight electrons.

$lement a +g Al 'i B ' l Ar

%roup number I II III I1 1 1I 1II Formula of ion a& +g2& Al%& - B%- '2- l- -

ch1.2 periodic table lesson material

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