Molecules and Covalent Bond

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1 Molculs and ovalnt ond Qustion Papr 1 Lvl IGSE Subjct hmistry (0620/0971) Exam oard ambridg Intrnational Examinations (IE) Topic toms, lmnts and compounds Sub-Topic Molculs and covalnt bonds ooklt Qustion Papr 1 Tim llowd: 48 minuts Scor: /40 Prcntag: /100 Grad oundaris: >85% 75% 68% 60% 53% 48% % 33% <25%

2 1. ovalnt bonds ar formd whn lctrons ar 1. ovalnt compounds hav 2 lctrical conductivity. Which words corrctly complt gaps 1 and 2? 2. Th lctronic structurs of atoms X and ar shown. X X and form a covalnt compound. What is its formula? X 5 X 3 X X 3 3. Which diagram dos not show th outr shll lctrons in th molcul corrctly? l l l 2

3 4. Elmnt X has six lctrons in its outr shll. ky = lctron ow could th lmnt ract? by gaining two lctrons to form a positiv ion by losing six lctrons to form a ngativ ion by sharing two lctrons with two lctrons from anothr lmnt to form two covalnt bonds by sharing two lctrons with two lctrons from anothr lmnt to form four covalnt bonds 5. In which compounds ar pairs of lctrons shard btwn atoms? sodium chlorid mthan lad bromid 1 only 2 only 1 and 3 1, 2 and 3 3

4 6. Th diagram shows th lctronic structurs of atoms P and Q. ky = lctron = nuclus P Q P and Q combin to form a molcul. What is th formula of this molcul? PQ 4 PQ P 2 Q P 4 Q 7. In th diagrams, circls of diffrnt sizs rprsnt atoms of diffrnt lmnts. Which diagram rprsnts hydrogn chlorid gas? 8. In th molculs 4, l and 2 O, which atoms us all of thir outr shll lctrons in bonding? and l and l and and O 4

5 9. Elmnt X forms an acidic, covalnt oxid. Which row shows how many lctrons thr could b in th outr shll of an atom of X? 10. Which is a simpl covalnt molcul? conducts lctricity whn solid whn moltn volatil 11. Th diagrams show th lctron arrangmnts in th atoms of four lmnts. Which lmnt dos not form a covalnt bond? ky lctron nuclus 5

6 12. Which statmnt about th bonding in a molcul of watr is not corrct? oth hydrogn and oxygn hav a nobl gas configuration of lctrons. Each hydrogn shars its on lctron with oxygn. Oxygn shars on of its own lctrons with ach hydrogn. Oxygn shars two of its own lctrons with ach hydrogn. 13. Elmnt X has six lctrons in its outr shll. ky = lctron ow could th lmnt ract? by gaining two lctrons to form a positiv ion by losing six lctrons to form a ngativ ion by sharing two lctrons with two lctrons from anothr lmnt to form two covalnt bonds by sharing two lctrons with two lctrons from anothr lmnt to form four covalnt bonds 14. Elctrons from ach lmnt ar shard by both of th lmnts in a compound. Which compound matchs this dscription? lad bromid sodium chlorid watr zinc oxid 6

7 15. Sodium chlorid is an ionic solid. Which statmnt is not corrct? Ions ar formd whn atoms los or gain lctrons. Ions in sodium chlorid ar strongly hld togthr. Ions with th sam charg attract ach othr. Sodium chlorid solution can conduct lctricity. 16. asium chlorid and rubidium bromid ar halid compounds of Group I lmnts. asium chlorid has th formula 1, a rlativ formula mass 2 that of rubidium bromid and bonds that ar 3. Which words corrctly complt gaps 1, 2 and 3? al diffrnt from ionic al th sam as covalnt sl diffrnt from ionic sl th sam as covalnt 17. Elmnt X is in Group I of th Priodic Tabl. X racts with lmnt to form an ionic compound. Which quation shows th procss that taks plac whn X forms ions? X + X + X X X + X X X + 7

8 18. Th lctronic structurs of atoms X and ar shown. X X and form a covalnt compound. What is its formula? X 5 X 3 X X In th following diagrams, X and ar atoms of diffrnt lmnts. Which diagram corrctly shows th arrangmnt of outr lctrons in a molcul of mthan? X X X X 20. In which compounds ar pairs of lctrons shard btwn atoms? mthan lad bromid sodium chlorid 1 only 2 only 1 and 3 1, 2 and 3 8

9 21. Which statmnt about bonding is not corrct? arbon can form four singl covalnt bonds. hlorin atoms ract to gain a nobl gas lctronic structur. ovalnt bonding involvs losing and gaining lctrons. ydrogn molculs hav th formula ovalnt bonds ar formd whn lctrons ar 1. Most covalnt compounds hav 2 lctrical conductivity. Which words corrctly complt gaps 1 and 2? 23. Th tabl shows th lctronic structur of four atoms. Which two atoms combin to form a covalnt compound? W and X W and X and X and Z 9

10 24 n atom of lmnt Q contains 19 lctrons, 19 protons and 20 nutrons. What is Q? calcium potassium strontium yttrium 25. Which molcul contains only singl covalnt bonds? l 2 O 2 N 2 O Ethn is an unsaturatd hydrocarbon. Which dscription of th bonding in thn is corrct? ll atoms in th molcul hav a shar of ight lctrons. Each carbon atom shars two of its lctrons with hydrogn atoms and two of its lctrons with a carbon atom. Each carbon atom shars two of its lctrons with hydrogn atoms and on of its lctrons with a carbon atom. Th two carbon atoms shar a total of six lctrons with othr atoms. 10

11 27. Elmnt X forms an acidic, covalnt oxid. Which row shows how many lctrons thr could b in th outr shll of an atom of X? 28. Which diagram dos not show th outr shll lctrons in th molcul corrctly? l l l 11

12 29 Substancs with giant covalnt structurs can b usd as lubricants and as cutting tools for hard matrials. Th diagram shows how th atoms ar arrangd in two giant covalnt substancs, X and. X ky strong covalnt bond wak attraction Which statmnt is corrct? Only X is usd as a cutting tool and only is usd as a lubricant. Only X is usd as a lubricant and only is usd as a cutting tool. X and ar both usd as cutting tools. X and ar both usd as lubricants. 30 Which dot-and-cross diagram shows th outr shll lctron arrangmnt in a molcul of nitrogn? N N N N N N N N 12

13 31 Which dot-and-cross diagram shows th outr shll lctron arrangmnt in a molcul of carbon dioxid? O O O O O O O O 32 Which dot-and-cross diagram shows th outr shll lctron arrangmnt in a molcul of carbon dioxid? O O O O O O O O 33 Which molcul contains xactly two singl covalnt bonds? l 2 4 2O l 13

14 34 Which lctron arrangmnt for th outr shll lctrons in a covalnt compound is corrct? l l N N 35 Which statmnt about a molcul of ammonia, N 3, is corrct? Each hydrogn atom donats a pair of lctrons to a nitrogn atom. Thr ar doubl covalnt bonds btwn th nitrogn atom and th hydrogn atoms. Thr ar singl covalnt bonds btwn its hydrogn atoms. Thr ar thr shard pairs of lctrons in th molcul. 36 covalnt molcul M contains a total of four shard lctrons. What is M? ammonia, N 3 hydrogn chlorid, l mthan, 4 watr, 2 O 14

15 37 Solid F is an lmnt. Solid G is a compound. Nithr solid conducts lctricity but G conducts lctricity whn dissolvd in watr. Ths proprtis suggst that F is 1 and that G is 2 with 3 bonds. Which words corrctly complt gaps 1, 2 and 3? 38 ompound X mlts at 801 and is a good lctrical conductor whn dissolvd in watr. ompound boils at 77, is insolubl in watr and is a non-conductor of lctricity. Which typ of bonding is prsnt in X and in? 15

16 39 In which row do th proprtis dscribd match th typ of bonding? mlting point lctrical conductivity whn liquid typ of bonding high dos not conduct ionic low conducts covalnt low conducts ionic low dos not conduct covalnt 40 Th diagrams, X, and Z, show part of a polymr and two giant covalnt structurs. X Z Which of X, or Z could b usd as a cutting tool and which of X, or Z could b usd to rduc friction? 16

3.2.3 Molecules and Covalent Bonds

3.2.3 Molecules and Covalent Bonds Sav My Exams! Th Hom of Rvision For mor awsom GSE and lvl rsourcs, visit us at www.savmyxams.co.uk/ 3.2.3 Molculs and ovalnt onds Qustion Papr Lvl IGSE Subjct hmistry (0620) Exam oard ambridg Intrnational