chem worksheet
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AWnuuCHIJ ST THERESA'S CONVENTSec 3 Express Science Chemistry (Past Year Examination Questions)Atomic Structure and Chennical Bonding
h0\014 6aJNov03/P3/Ql2flanteidrnortcvnHlrlltosezva\enca.(ectv?rufoatt'tihal':'Adfrrlfti;; eiliili'dnlaf op -+3"r''s 8l '
a)i) A calcium ion has an electrical charge. Explain how, and why, this ion becomes chargedwhen it is formed from an atom.ii) Give, using diagrams, the electronic structure of a calcium atom and a calcium ion. [7]
.#'";electrons.{a} complete Fig. 6.1 to describe the particles in the calclum iort.
electrical chargpositive chorge
neuiraIcha
Fig.6.1(b) How does the formafion of the calcium ion show that calcium is a metal?
{Ca ionlr5:r
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Celctqrn lose i1s Zv4lnc eteth0ns {o torm (-r) ions .t1 Itc) How willanother isotope of calcium
(l) differ from !f,Ca,. . .D'Jf*nf ..119 ...$. nr$ry-r
. ..ryK-t$l... 1:nA P,.lsse .Elenqs..:qleIff.o.ru n'.S:m P.o$1ivs .iw.S
(lU be the same as $f;Ca? r A -,giivneno 4 ngII .. l]9),..$9.Y.(...9J9'!11*{)f.:1..:.1.!.. . .... . ..t21
b) An isotope of calcium has a mass number of 40. Another isolo-pe of.c.alcium has a mass' numb er'o| 44, What does the nucleus of each isotope contain? ir t3ln rrl r2, tv,n - 6A ? nl dliyy| - I+tl ,,/#f\. I I
number lrtone Caz+ ion
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Nov 04/ P3/ Q9a) Atoms with two e!gq!q!g sell can combine with atoms with sevenelectrons in tFeii ouEimost shell. Draw cross' diagrams to show suchcombination. Name tne atoms and the compounds formedl BefY[iUm F\Uffide t6]b) t*o'"tn#lil"n ionic compounds win conduct etectricig,tvnlflP ims ,{ree to condqct tKiytdty
iD solid ionic compounds will not conduct electricity. t4ln6 yltbile io{tJ r not frft fo - . -.t/vlc\^e {o oncluct elecv(qNov Oil P3/ QG' Fig. 6.1 contains drawings of the nuclei of five diflerent atoms, l, J, K, L and
IJKM.
keyproton Oneulron O
Fig.6.lWhich ol the atoms l, J, K, L and M(o) are isotopes of the same efement,r$n no =somg l rM
has a nucleon number of thre6,L
(cl have one electron in their outermost eleetron shell,L (no. of Petr4' {tCtton)(d) is given the symbol lLi?
i\t1l ' -/(b)
tl l
rllI rl
t1]
L ro. ooo
I o.^, oo a" ot
t ! lrsty: J neuctroyr)Page 2 o1'6
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Nov Oil P3/ QTFig.7.1showe the arrangement of elsctrons of an element from one of the Groups of thePeriodic Thble shourn on paga 12.
keyelectron anucteus @
Fig.7.1Draw in the space below the arangement of electrons of another alemenl in the oameGroup.- 0/cuP c
2- A'6 tzl(b) The element shown in Fig.7.1 reacts wlth hydrogen. Draw a diagram in the space belowto show th arrangment of electrons in the compound formed in this reaction.
(a)
- ofe- of ||ydt"ogzrtoxYOen
{av--'-=-/ W il-o{ carbcvr( Nov 061P3/ Qe n i e o{ cxrlSeh\ u) il Name the type oJ chemical bond found in a molecule of carbon dioxide. COVAtehf-----ii1 Draw a ' dot and cross' diagram to show the anangement of electrons in a carb-oridioxide molecule. Only the outer electron shells need to be shown. tnb) Substances with the chemicalbond found in carbon dioxide normally have a relativelylow boiling point. Explain why,
t3I
t3lrha covqlht rnotecu(e ie he{d +ogether lry r.reqk irte!'vnoteetpF-.+gl8sot oftracten . onry qe.,'narl 3*ynt 4 rnewJy '(*rql.rirel ro o$ncqyla1!rr wwE {rce of offruct{on .
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Nov 07/ P3/ Q7Fig.7.1 ehov*a the structuregasecus hYdrogen ctlbrid- ol solid sodium chlorlde and Fig.7.2 shows the structure of
Flg.7.1solidsodium chloride
Flg.7.2ga$oushydrogen chloride {)
forca & afuactiu
keyodiurfl lon with positive cfiarge g hydrogen atom with no charge ocitorid lon wlh ncgativa charge e chbrine atom wllh no charge qp
(a) Explain why sodium chloride has a very high meltlng point..1j9(4 .irs..mqdg.$n.*....S.1)*gnq!J..ipyu ..ptnat lhil. )"{s1.,111.in..{S.n.lJb$! !9ys 9M fj$L...;:ll3 {rt.gtlKsl iqxs{Lxs :ll b,qh thesc hgt.{Lzt durolft
{b) (l} Exptain wfry sodium chloride wilf conduct electricity when molten.r!1 llDlten sfiIr.r..f9K t9.-Msyl . t31.tr. lrgJg nsp1o o,Auct etrc{ricdy t,
(ll) When allorrved to soliclify sodium chtorlde loses the ablllty to c.onduct olectriclty.Explain why,
l1^4rc n no rrroblle irlrrr to m114.t'.,gn9!...ccn9l$SJ..f !9Jlr-i31y.,,...,...(c) Hydrogen ctrlorlde dissolves in watar to form an acidic solution.
t3l
%-#ffi
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Nav 07/ P3/ Q9An element has an isotope with fte nucleon nurnhar 9,Fach of tha isotopa'e neutral etorrs hag foqrr elec#ons andtps*rt p$fide, a nucleus containing tm different(*) Sive ffre namss of lfreee. pafiicles and the. numbgr of aath partlde presenlin each nuclaus.(b){c}
Gompare the masses and compare lhe etectrical changre of these particles. l3lThs elemant has another isotope wilh atoms that have a nucleon number of ten.Compare and contrast the nuclelof theseturo i$otopes. t3]
3 This table shows some intormalion about atoms ol the elements W, X, Y and Z.{The letters do not represent th atomlc symbols of the elements,)
(i) Complete the table by filling in the information for element Z. t3l(ii) Give a reason why element Z is likely to be a metal. rlvretal and ro t0s iff valence..r:..,j:.,g..T...pgsjl.*...i.ft../.......... 11l"iiitt if "Air'+ddt1A' ih "Alinp'i .4,ir r.(ll Describe the change In elec#onlc configuration that occurs to an atom of elementW when itforms an ion.. H.fll gqln l:lq-.lpn: P. !:r* 91 l;Ifff$ d ?-3:9 rrr
(ll) The accurate relative atomic mass of element W is 32.1.Explain why this is not a whole number.. ..ffi...fr* i1 .L19 1u- .ru"n.99...*. i:ot?}.g:.., .. ..... ..
................t11Elements X and Y cornbine to form a covalentfy bonded molecule.Draw a'dot and cross'diagram to show the bonding in thls molecule.Your diagram only needs to show outer electrons.
' Frotoyl, hetfron t rsutopefl |
I a6, 5 neqtohJ I K6t?eiz t4lI 4grctons
: e-ol; e- o
{a}
(bl
xY
xe
element atomlcnumber number ofprotong number ofneutrons massnumberelectronlccorrfiguratlon
w 16 16 16 g2 2.8.6x 7 7 7 14 2.5Y 1 1 1 2 1z 11 ll 12 23 2.8. I
(c)
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* This information comes from a website about salt't*I Cornmon Salt& S^ttcontains lhe csmp.gund sodium chloride'E n tingf* salt crystal consists of a
vast ionic lattice offi sodium and chloride ions.$wI fna lattice structure mans that salt crystals are very# *ara and have regular ehaPes.1.nI A verv imoortant usa of salt is to provlde tho hugeE "*ountt of chlorine that are used every day' Chlorine is* made industrially by electrolysis of concentrated'7,.f. aqueous soolum cnnride, This produces chforine asi an elemsnt.ft -_i
(a) The websile uses the words elomentand compound'
Na* @ cl- C
i _)Explaln what thoee words mean'eremenr . $..ryx syP-41ng..11.:1lls. *. opft .'.{: .}. 1 } *....-.jna'" Y?u@hnn. .9,g,n^,gl..qgg.t.{. -e!9:Y.,:Y..i...,. .. . .
tb) Explain why the lattice structure ol sodium chloride cau$ee the cry$tals to be 'veryhard'and have 'regular shapee" ,.T.F-ll* s .r*.{s.*P..* l-o-'$r.r\..?\?w..!ttll .iss %4 I. ion',T\4e force 4 attractiun beftveevr 0.PP..0rqJY.,,9.h9.fE:*.....(q\c...??-..Y:YS\To\nq......'..'rif anot herre +tt\e kr'rs qr ?y!W{....9.ftn.*....,.............. rzt \ )6iqnt{afrticecvytqt
etrucilre- +\^a't OMe K its l"egrtOr sharg'
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