Chapter 7 - Periodic Table

8/9/2019 Chapter 7 - Periodic Table

1/19

CHAPTER 7

PERIODIC TABLE

1. Matter in our universe is made of about 100 chemical elements. The periodic

Tables make the study of chemistryof these elements easier.

2. Scientists are thankful to Dobereiner, Newlands, Meer, Mendeleev and Moselewho made !reat contributions to the development of the "eriodic Table.

#. The "eriodic Table contains elements that arran!ed with their proton numbers in

increasin! order.$. The horizonta of the periodic table !coumns" is known as a #rou$ and the

%entrice !ro&s"of the periodic table is known as a $eriods'

%. There is 1& #rou$s and elements are !roupin! (y identified the eectron

%aence. The same electron valence is in the same !roup.'. (lements in the same !roups have same chemical properties.

). *toms in #rou$s )* + and ,have 1, 2 and # electron in the outermost electron

valence. *ll the elements are metas. *toms in #rou$s )-* ).* )/* )7 and )0are

non1metas.&. *ll metals are on the left side and non+metals are on the ri!ht side of the periodic

table.. (lements in the same !roup have the same number of outermost electrons and

similar chemical properties.

10. There are 7period in periodic table. *ll elements in the same periods have thesame orbits of electron valence. "eriods 1, 2 and # have 1, 2 and # orbit of

electron valence.

11. The proton numbers increase across the period and atomic si-e decrease.

12. The elements in !roup # to !roup 12 are called transition eements'1#. The elements in the first row are called anthanoidsthe old name is lanthanides/.

The elements in the second row are called the actinoids the old name isactinides/."(D3 T*45(

1 2 1# 1$ 1% 1' 1) 1&

6 6e

5i 4e

Transition elements

4 3 N 7 Ne

Na M! *l Si " S 3l *r

8 3a Sc Ti 9 3r Mn 7e 3o Ni 3u :n ;a ;e *s Se 4r 8r

b Sr < :r Nb Mo Tc u h "d *! 3d n Sn Sb Te =e

3s 4a 5u 6f Ta > e s r "t *u 6! Ti "b 4i "o *t n

7r a 5r f Db S! 4h 6s Mt

1


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(?ercise@ 3omplete the table below with the 3hemical Smbols of the elements.

;roup Name 3hemical Smbols of the elements.

1 *lkali metal 5i, Na, 8, b, 3s, 7r 2 *lkali earth metal 4e, M!, 3a, Sr, 4a, a

1) 6alo!en 7, 3l, 4r, , *t

1& Noble !as 6e, Ne, *r, 8r, =e, n

1$. There is a number &ritten a(o%ethe chemical smbol of the element in each bo?.

t starts with number 1, increases b one unit as we move to the ri!ht, and ends

with number 112.1%. This number used to be called atomic num(er. t is now called $roton num(er.

"roton number is the num(er of $rotons in an atom of an eement. 7or

e?ample, the proton number for o?!en is &. t means that o?!en atom has ei!ht

protons.1'. The proton number also indicates the num(er of eectrons in an atom of an

element. This information and the position of the elements in the "eriodic Table

enable us to write the electron confi!uration of the elements.

A' Eectron confi#uration

1. *n atom is made of a ver small nucleus in the centre and one or more electrons

outside the nucleus

2. *n eectron confi#urationindicates ho& the eectrons are arran#edoutside thenucleus

#. The first shell has a ma?imum of +electrons. The second shell and the rest of

shells has a ma?imum of ei#htelectrons$. The electron confi!uration of an element indicates its !roup and period. ;roup 1

has 1 electron in their outermost.

%. (?amples@

2

&

1'.00

"roton

number

22

2

electrons

nucleus

#

5i

2.1

"roton

number(lectron

confi!uration

3hemical

smbol


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a/ The electron confi!uration of lithium chemical smbol, 5i/ is 2.1. t is made

up of two numbers separated b a dot. The two numbers indicate that the

element is in "eriod 2. The last number is 1, indicate that the elements is in;roup 1. The sum of all the numbers is #, which is the proton number of

lithium.

b/ The electron confi!uration of chlorine chemical smbol, 3l/ is 2.&.). t ismade up of three numbers separated b two dots. The three numbers indicate

that the element is in "eriod #. The last number is ), indicatin! that the

element is in ;roup 1). The sum of all the numbers is 1), which is the protonnumber of chlorine.

c/ the last number in the electron confi!urations is the same for all the elements

placed in the same !roup and the proton number increases b one as we move

from one element to the ne?t, that is from left to ri!ht

Acti%ity 7'+3 Eectron confi#uration

"art of the "eriodic Table below shows elements with proton numbers 1 to 20 onl. Theseelements are in ;roup 1, ;roup 2, ;roup 1# to ;roup 1&, and in "eriod $. The number or

numbers written below the chemical smbol of selected elements are the electronconfi!uration of the element. Stud them and then write the electron confi!urations for

the other elements.

B' 4aturay1occurrin#* radioacti%e and synthetic eements

1. Some of elements are radioacti%e'adioactive elements emit harmful radiations,such as !amma ras and =+ras. The last elements in several !roups and all

actionoids are radioactive. Some e?amples are francium, 7rA astatine, *tA radon,

nA and uranium, B.

E5ercise 7')

1. 6ow man elements is a/ in ;roup 1$C b/ n "eriod $C

2. >rite the chemical smbol of the alkaline earth metal in "eriod # and the first

transition metal in "eriod %.

#. The electron confi!uration of the element with proton number is

$. The electron confi!uration of an element ? is 2.&.&.2. (lement = is in ;roup and

"eriod . ts proton number is and its chemical smbol is .%. The proton number increases across a period and down a !roup. ETrueF7alseG.

'. (lement = electron confi!uration 2.2/ and element < electron confi!uration 2.&.&.2/

are in the same !roup. ETrueF7alseG

#


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). (lement H electron confi!uration 2.#/ and element electron confi!uration 2.&/ are

in the same period. ETrueF7alseG.

6ROP )S7T M(T*5S/

1. There are si? elements in ;roup 1. The elements are lithium, 5iA sodium, NaApotassium, 8A rubidium, bA caesium, 3sA and francium, 7r. Notice that their

names have the endin! IiumJ. This is because these elements are metas.

(lements (lectron confi!uration utermost electrons

5ithium 2,1two orbit with one electron in the

outermost/

Sodium 2,&,1

three orbit with one electron in the

outermost/

"ottasium 2,&,&,1 four orbit with one electron in theoutermost/

ubidium 2,&,&,&,1

five orbit with one electron in the

outermost/

3aesium 2,&,&,&,&,1 si? orbit with one electron in theoutermost/

A' Physica and chemica $ro$erties

1. The characteristic of elements in !roup 1

Physica $ro$erties Chemica $ro$erties

8oft metas

5ithium is harder and has hi!her meltin! point than

sodium, and that sodium is harder and has a hi!hermeltin! point than potassium.

Donate an electron to form

ionic atoms.

Na + e NaK

The meltin! point and the boilin! point are decreasedown the !roup.

eactivit of elements in!roup 1 is increase down the

$


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(lement adiusF

nm

elative

atomicmass

DensitF

! cm+#

Meltin!

pointFo

3

5ithium 0.1' '. 0.%# 1&1

Sodium 0.1 22. 0.) &

"otassium 0.2$ #.1 0.&' '#

These elements are metals. Thus, their atoms are

bonded to each other b metaic (ondin#. *s the

si-e of the atom increases, the stren!th of themetallic bond decreases. This will make the

element with a (i##er atom softerand has a lower

meltin! point.

!roups.

;ood conductor eact with water to formalkali solution metal

hdro?ide/ and hdro!en!ases. * lot of heat is also

!iven out.

The !eneral eLuation for

the eLuation is@

2M K 262 2M6 K 62Metal >ater Metal 6dro!en

hdro?ide

25i K 262 25i6 K 62

5ithium >ater 5ithium 6dro!en6dro?ide

2Na K 262 2 Na6 K 62

Densit increasedown the !roup

5ithium has the lowest densit in the !roup

because its relative atomic mass is the lowest.

4urn with o?!en to formmetal o?ide.

Na K 2 Na2

4urn with inert !ases to formmetal halide.

Na K 3l2 Na3l

%


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B' Predictin# the $hysica and chemica $ro$erties of other 6rou$ ) eements

1. t is difficult to stud the phsical and chemical properties of ubidium ,3aesiumand 7rancium

2. Their phsical and chemical properties b studin! the chan!es in the phsical

and chemical properties of lithium, sodium and potassium.#. 7or e?ample, a !raph of meltin! point versus proton number can be used to

estimate the meltin! points of rubidium, caesium and francium. The meltin!

points of rubidium and caesium are #o3 and 2o3 respectivel

$.

C' The $osition of hydro#en in the Periodic Ta(e

1. The electron confi!uration of hdro!en is 1. This su!!ests that the element shouldbe in "eriod 1 and ;roup 1. Some "eriodic Table shows that hdro!en in "eriod 1

but not in ;roup 1.

Acti%ity 7',3 The $osition of hydro#en in the Periodic Ta(e

The actual phsical and chemical properties of hdro!en are !iven in table below. >rite

the e?pected properties of hdro!en if it is a ;roup 1 element located above lithium. Theactual phsical states are alread written for ou in the Table ).#. s there an a!reement

between the actual and e?pected valuesC

"ropert *ctual (?pected if in;roup 1

"hsical state ;as Solid

DensitF! cm+# &. ? 10+%

Meltin!pointFo3

+2%

eaction withwater

No reaction

'

0 20 $0 '0 &0 100

#0

'0

0

120

1%0

1&0

"roton number

Meltin!

point.o3/

5i

Na

b

3s

7r

8

* !raph of meltin! point versus proton

number for !roup 1 elements.


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2. n fact, hdro!en does not belon! to an !roup. t is in a !roup b itself

E5ercise 7'+

1. >rite an eLuation for the reaction of rubidium with water.

2. The hardest element in ;roup 1 is and the most reactive element is

#. The meltin! point of the elements in ;roup 1 increases from 5i to 7r. ETrueF7alseG.$. The softest ;roup 1 metal has the lowest meltin! point. ETrueF7alseG.

%. 6dro!en is in "eriod 1 of the "eriodic Table. ETrueF7alseG.

'. 6dro!en is not a ;roup 1 element because it is a !as at room temperature.

ETrueF7alseG.

6ROP )76*5;(N/

1. There are onl five elements in ;roup 1), namel fluorine, 7A chlorine, 3l,bromine, 4rA iodine, and astatine, *t.

Name electron confi!uration outermost electrons

7luorine 7 2,)

two orbit with seven electron in the

outermost/

3hlorine 3l 2,&,)

three orbit with seven electron in the

outermost/

4romine 4r 2,&,&,)

four orbit with seven electron in the

outermost/

odine 2,&,&,&,) five orbit with seven electron in the

outermost/

*stantine *s 2,&,&,&,&,)

si? orbit with seven electron in the

outermost/

)


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A' $hysica and chemica $ro$erties

1. The characteristic of elements in !roup 1)"hsical properties 3hemical properties

Non+metals and e?its in sim$e diatomicmolecules =2.

7or e?ample, the chemical formula of chlorine, bromine and

iodine is 3l2, 4r2and 2,

3hemicalformula

elativemolecular

mass

"hsicalstate

3olour DensitF!cm+#

4oilin!pointFo3

3l2 )1 ;as "ale

ellow

1.'' +#$.0

4r2 1'0 5iLuid Dark

red+

brown

#.1 %.%

2 2%$ Solid 4lack #.' 1&%.2

The most reacti%e non

metals

The reactivit o

elements in !roup 1) idecrease down th

!roup.

The meltin! point and boilin! point a o&.

These molecules are attracted to each other b weak forces,

known as 9an der :aas forces. The stren!th of these

forces increases when the molecular si-e increases. The si-eof chlorine molecule is smaller than bromine and iodine

molecules. Thus, the 9an der >aals forces between chlorine

molecules are weaker than between bromine and iodine

molecules. t follows that chlorine has a lower boilin! pointand e?ists as a !as at room temperature.

eact with water to form

acidic soution'

f = represents ;roup

1) elements, the !eneraeLuation for the reaction

with water is

=2K 62 6= K 6=

6= and 6= are acids

6= is also a bleachina!ent. Thus, the chan!

the colour of th

universal indicator from!reen to initiall red an

finall colourless

Densit is low. eact with metals hdro?id

to form salts.

The !eneral eLuation fothe reaction with an

aLueous solution of

sodium hdro?ide is

=2K 2Na6 Na=KNa=K 62

Na= and Na= ar

salts. Na= is also

&


9/19

bleachin! a!ent. Thu

the products of thabove reaction wi

chan!e the colour of th

universal indicator from

!reen to colourless.Not !ood conductors. eacts with sodium and iron

The !eneral eLuations

for the reaction of

;roup 1) elements with

sodium and iron are@=2K 2Na 2Na=

#=2K 27e 27e=#There are solutes in or!anic solution.

C' Predictin# the $hysica and chemica $ro$erties of other 6rou$ )7 eements

1. 7luorine is the most reactive element known. *statine is radioactive and instable

Acti%ity 7'-3 Physica and chemica $ro$erties of fuorine and astatine

The phsical and chemical properties of fluorine and astatine can be predicted b

studin! the chan!es in the phsical and chemical properties of chlorine, bromine andiodine. Stud the phsical and chemical properties of these three elements and then

complete the table for fluorine and astatine.

7luorine *statine

3hemical formula

"hsical state

3olour

Densit

4oilin! point

"roducts from the reaction with Na6aL/

eaction eLuation for the reactionwith Na

elative reactivit More reactiveFless reactivethan chlorine

More reactiveFlessreactive than


10/19

iodine

hi!hli!ht the correct answer

E5ercise 7',

1. n ;roup 1), the chemical smbol of the elements lar!er than bromine is ,and the most reactive element is .

2. write an eLuation for the reaction of astatine with@

a/ 62b/ Na6

c/ Na

d/ 7e#. 7luorine is a colourless !as. ETrueF7alseG.

$. The products formed from the reaction of 4r2with Na6 are Na4r and Na4r.

ETrueF7alseG.%. Na3l chan!es the colour of the universal indicator from !reen to initiall red and

finall colourless. ETrueF7alseG.

6ROP )0 N(T ;*S(S /1. 8nown as inert #as or no(e #ases.

2. The elements in this !roup are in sta(esituation because their

outermost eectron are octet ! count of 0 "'

#. The elements is 6elium 6e, Neon Ne, *r!on *r, 8rpton 8r,

=enon =e and adon n.

$. There are radioactive, unreactive !ases and used as

adon 3ancer therap.

Neon Bsed in advertisement li!hts.

*r!on Bsed in incandescent li!hts bulb.*r!on !as is mi?ed with nitro!en !as in incandescent li!ht

bulbs to prevent the tun!sten filament from burnin!.

8ripton Bsed in traffic li!ht and flash camera.

?enon Bsed as laser.

6elium Bsed in weather balloons.

3ombine with o?!en as a divin! tank !ases.

%. The phsical properties of !roup 1& down write the table isi. si-e atoms are increasin!ii. densit of elements are increasin!

iii. meltin! point and boilin! point are increasin!

(lement 3hemical

smbol

Densit

F!cm+#4oilin!

pointFo3

6elium 6e 0.0001) +2'&.

10

He

Ne

Ar

Kr

Xe

Rn


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Neon Ne 0.000&$ +2$%.

*r!on *r 0.001'' +1&%.)

8rpton 8r 0.00#$' +1%2.

=enon =e 0.00%$% +10'.

adon n + +

iv. The elements of ;roup 1& e?ist as colourless, monoatomic !ases.

v. The do not form com$oundnaturall with an elements. The are

said to be inert.

'. The chemical properties of elements in !roup 1& isi. Bnreactive !ases.

ii. ;ases in room temperature and stable free atoms/.

Acti%ity 7'.

The reationshi$ (et&een inert characteristics and eectron confi#urations'

The elements of ;roup 1 and ;roup 1) are ver reactive while the elements of ;roup

1& are inert. 3ompare the last numbers in the electron confi!urations of these elements

and then answer the followin! Luestions.

;roup 1 ;roup 1) ;roup 1&

6e

2

5i

2.1

7

2.)

Ne

2.&

Na

2.&.1

3l

2.&.)

*r

2.&.&8

2.&.&.1

4r

2.&.1&.)

8r

2.&.1&.&

b

2.&.1&.&.1

2.&.1&.1&.)

=e

2.&.1&.1&.&

3s

2.&.1&.1&.&.1

*t

2.&.1&.1&.#2.)

n

2.&.1&.1&.#2.&

7r

2.&.1&.1&.#2.&.1

a/ >hich element has a duplet electron arran!ement in the outermost shellC

EOdupletP means OtwoPGb/ >hich element has an octet electron arran!ement in the outermost shellC

EOoctetP means Oei!htPG

c/ *n atom with a duplet or an octet of outermost electrons is inert. ETrueF7alseG

E5ercise 7'-

11


12/19

1. The element in ;roup 1& that has the lowest boilin! point is , the

smallest atom is , and less dense than air is .

2. The 9an der >aals forces in 6elium6e/ is stron!erFweaker than in NeonNe/.#. The atoms of ;roup 1& elements have either a duplet or an octet of outermost

electrons. ETrueF7alseG

$. 5iLuid helium is used as a coolant because it has a ver low boilin! point.ETrueF7alseG

%. adon is used to kill cancer cells because it is radioactive. ETrueF7alseG

PERIOD ,

;roup 1 2 # 1$ 1% 1' 1) 1&

"roton number 11 12 1# 1$ 1% 1) 1) 1&

Smbol Na M! *l Si " S 3l *r

"hsical

characteristic

metal metalloid Non+metal

Solid conductor Solidsemiconductor

Solid or !as insulator

A' Atomic size

1. "roton number increases across the $eriod. The proton number indicates the

number of protons in the atomic nucleus.2. Thus, it is able to attract the outermost ne#ati%ey1char#ed eectrons coser to

it. This reducesthe si-e of the atom

B' Acid1(ase $ro$erties

1. The phsical characteristic of the elements chan!es from metal sodium,ma!nesium, aluminum/ to metaoidsilicon/ to non+metal phosphorus, sulphur,

chlorine and ar!on/.

2. M! reacts with 2 to form M!. Ma!nesium o?ide is onl si#hty sou(e inwater. Metal o?ide reacts with acid to form sat and &ater. This means that

ma!nesium o?ide is a (ase. n !eneral, metallic o?ides are bases.

2M! K 2 M!M! K 263l M!3l2K 62

#. Silicon dio?ide, Si2is a compound of silicon. t is insoluble in water, does notreact with acids, but reacts with stron! bases, such as sodium hdro?ide.

Si2K 2Na6 Na2Si#K 62

$. Sulphur burn in air to form sulphur dio?ide S2. The !as react with water to form

acid rain.

12


13/19

S K 2 S2S2K62 62S#

C' ses of metaoids

E5ercise 7'.

1. n "eriod # of the "eriodic Table, the elements are metals,

is a metalloid and are non+metals.

2. Metalloids are conductorsFsemiconductorsFinsulators.#. Name two elements in "eriod # that react with o?!en to form basic o?ides.

$. Silicon dio?ide reacts with 63lFNa6.

%. The elements that are added to silicon to improve its conductivit are from ;roup1# and ;roup .

TRA48ITIO4 ELE;E4T8 O< PERIOD -

1#

Uses of silicon in daily lifeSilicon is the second element in Group 14. It is a metalloid. This meansthat it is an insulator at room temperature and a conductor whenheated. However, this characteristic is not suitable in electrical devicesas its electrical conductivity would depend on temperature.

The electrical conductivity of silicon at room temperature isincreased by adding a small amount of an element from Group 1 toGroup 1!. "or e#ample, adding boron $a Group 1 element% produces ap&type semiconductor while adding arsenic $a Group 1! element%produces an n&type semiconductor.

' transistor is formed when n&type and p&type semiconductorsare (oined in the following way) p&n&p or n&p&n. ' transistor can controlthe *ow of electrons in circuits very accurately and re+uires very littlepower to operate. ' silicon chip, the sie of a -ngernail can hold morethan 4 million transistors in a single integrated circuit. Transistors arecomponents of modern solid&state electronic devices. Some electronicdevices that use transistors are televisions, calculators and high&speedcomputers.

'nother use of silicon is to mae solar cells. Solar cells convertsunlight into electricity. ' solar cell may be made up of a thinner layerof n&type semiconductor at the bottom. Solar cells are used incalculators, watches, spacecrafts, communication satellites, and as a


14/19

1. The transition elements in period $ are metals known as scandium, titanium,

vanadium, chromium, man!anese, iron, cobalt, nickel, copper and -inc. These

elements are situated from !roup # to !roup 12.2. The phsical properties of transition elements is

i. Metallic in color with shinin! surface.

ii. Mulur, boleh ditempa and boleh dire!an!.iii. 6ard and solid.

iv. 6i!h meltin! point and boilin! point.

v. 6i!h densit.

(lements 8 Sc Ti 9 3r Mn 7e 3o Ni 3u :n

Densit F

!cm+#0.&' #.00 $.%0 '.10 ).20 ).$$ ).&' &.&' &.0 &.2 ).1$

Meltin!

point F o3

'$ 1%# 1')% 100 1&0 12$$ 1%#% 1$% 1$%# 10 $1

vi. 3onductor in electricit and heat.

#. Transition elements easil reco!ni-ed because

i. The compounds are in color.

3opper / sulphate blue compound/3obalt ll/ chloride reddish compound/

ii. The ionic solution are in color.

3u2K+ blue solution7e2K + white !reen solution

7e#K + ellow+oran!e solution

Ni2K

+ ;reen solution3r#K+ !reen solution

3o2K+ redish solution.

iii. Naturall found as a color stone such as8romium batu delima + red/, nikel Q ferum batu -amrud R

!reen /, ferum Q titanium batu nilam + blue /

ferum Q man!an batu kecubun! + purple /

$. The uses of transition elements in dail life.

(lements uses

>aerin! 3opper and silver Makin! waer and water pipe ."aintin! Titanium l9/ o?ide Makin! paint, papers and plastic in

white in color.

*ccessor 3hromium, nickel,

silver, !old and

platinum

Makin! decorative materials and

eweller.

3olorin! hair

Titanium 3olorin! hair ellowish

1$


15/19

7erum, copper and

3obalt

3olorin! hair brownish.

Molibdenum 3olorin! hair reddish.

*llo 7erum and carbon Makin! steel allo/

nsulators

9anadium 9/o?side 3ontact process

7erum 6aber processNicle stwald process

E5ercise 7'/

1. Name the chemical smbol of this transition element, 8$E7e3N/'G.

2. 3opper 3u/ has lowerFhi!her densit than bromine 4r2/ and lowerFhi!her meltin!point than potassium 8/.

#. 5ist two uses of transition elements and their compounds.

E5ercise 7'7

1. The !ases ar!on, *rA nitro!en, N2and o?!en, 2are e?amples of elements F

compounds.

2. The liLuids water, 62 and ethanol, 36#3626 are e?amples elements F compounds.#. The chemical formula of sulphuric acid is 62S$. The elements in sulphuric acid are

, and .

$. 6ow man different elements are in copper / nitrates, 3uN#/2C

HB(STNS@

1. State the principal of elements arran!ed in the "eriodic Table.

2. (?plain the electron confi!uration of elements in !roups of "eriodic Table.

#. 5ist si? elements of ;roup 1.State their atomic number and their electronconfi!uration.

(lements *tomic number (lectron confi!uration

$. State the phsical properties and chemical properties of ;roup 1 decrease the !roup.

1%


16/19

%. 5ist si? elements of ;roup 1).State their atomic number and their electron

confi!uration.

(lements *tomic number (lectron confi!uration

'. State the phsical properties and chemical properties of ;roup 1) decrease the !roup.

). State two elements of ;roup 1& and e?plain their used.

(lements The uses

&. State two elements of "eriod # and "eriod $ and e?plain their uses.

(lements The uses

"eriod #

"eriod $

Re%ie& =uestion

8ection A

1. >hich of the followin! statements about the "eriodic Table is correctC

*. The elements are arran!ed in ei!ht !roups.

4. The inert !ases are in "eriod 1 to "eriod ).

3. There are ten transition elements in "eriod $.D. The actinoids are snthetic elements.

2. The electron confi!uration of element = is 2.&.%. (lements = is

*. in "eriod %.

4. in ;roup %.3. a non+metal.

D. a transition element.

1'


17/19

#. 6dro!en is not a ;roup 1 element because

*. ts proton number is 1.

4. ts electron confi!uration is 1.3. ts chemical formula is 62.

D. ts does not react with water.

$. *statine is a radioactive element in ;roup 1). >hich of the followin! statements is

true about astatineC

*. t is colourless.

4. ts meltin! point is lower than iodine.3. t is more reactive than fluorine.

D. t reacts with water.

%. >hich of the followin! chan!es that occurs across an period in the "eriodic Table isincorrectC

*. The proton number increases.4. The last number in the electron confi!uration increases.

3. The atomic si-e decreases.

D. The meltin! point increases.

'. >hich of the followin! o?ides is basicC

*. M! 4. Si23. S2 D. S#

). The followin! compounds are coloured, e?cept

*. 92% 4. E3r62/'G3l#3. 8Mn$ D. M!3l2

&. "otassium is a ;roup 1 element. >hich of the followin! statements about potassiumis trueC

. t is a metal.

. t is ver reactive.

. t is softer than rubidium.9. t reacts with bromine.

*. and 4. and 93. , and 9 D. , , and 9

. >hich of the followin! is true about all elements in ;roup 1&C. ;ases.

. nert.

. Stable.

9. 5ess than air.

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*. and 4. and 9

3. , and 9 D. , , and 9

10. >hich of the followin! statements is true about 63lC

t is covalent compound.

t has low meltin! point. ts hdro!en , 6 atom has a duplet

valence electron confi!uration.

9 t is insoluble in water.

* , and

4 and

3 and

D , , and 9

8ection B@

1 The electron confi!uration of element = is 2.&.2 .

a/ (?plain how element = ma achieve stabilit.

b/ >hat is the smbol for element =C

c/ Draw a dot and cross dia!ram for a compound formed between element =

and o?!en.

d/ >hat tpe of chemical bond is formed between an atom of = and an atom

of o?!enC

e/ State three characteristic properties of a compound with the chemical

formula =.

2 Sodium chloride, Na3l and carbon tetrachloride, 33l$are common laborator

chemicals.

a/ Draw the dot and cross dia!rams for the formation of Na3l and 33l$.

b/ 3ompare the stabilit of Na3l with Na and 3l2.

c/ (?plain the stabilit of 3 in 33l$.

d/ >hat is the difference in the electrical conductivit of Na3l and 33l$C

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Chapter 7 - Periodic Table