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DE ELHI PU UBLIC SC CHOOL NEWTOW N WN KOLK KATA SESSION 2013-201 14 CTION EXAMINA E ATION SELEC SS: X, SET T-A CLAS SUBJE ECT: CH HEMISTR RY LLMARK KS: 80 FUL TIME: 2 hrs. Answers s to this pap per must be e written on the paper provided p sep eparately. Yo ou will not be b allowed to write dur ring the firs st 15 minut tes. This time is i to be spen nt in readin ng the Ques stion Paper. . Thi is time given n at the hea ad of this pa aper is the time t allowe ed for writin ng the answ wers. This question paper cons sists of 5 pa ages Section I is a comp pulsory. Att tempt any four fo questio ons from Se ection II. The inte ended mark ks for quest tions or par rts of questi ions are giv ven in [ ] SECTION I (40 Marks) Attem mpt all que estions fro om this Se ection Questio on 1: A: Fill in the blan nks from th he choices given g below w: [5] a ) Salts of re epresentativ ve element ts are gener rally _____ ______ .(Co olourless/br right coloured) b) A covalent t bond betw ween two dissimilar d atoms is call led a _____ _____ coval lent bond. (Pol lar/ non-po olar) c) Generally an ionic co ompound undergoes _________ _ c chemical re eaction tha an covalent co ompounds. (Fast/slow w) d) An electro onegativity is an abilit ty of an ato om to attrac ct ________ __of electro ons towards it tself. ( Shar red pair/ lo one pair) l gas is app plied on a moist m litmus s paper it will w _____ red litmus s to e) When HCl blue.(Turn n/not turn) ) B: A group of ele ements in th he periodic c table are given g below w (Beryllium is the fir rst membe er of the group and Ba arium is th he last.) [5] Berylli ium, Magn nesium, Cal lcium, Stro ontium, Bar rium. a) Which W elem ment has th he least met tallic chara acter ? b) Which W elem ment is exp pected to ha ave the low west electro negativity? ? c) The atomic c number of o the magn nesium is 12. Write th he chemical l formula of o the compound formed wh hen magnesium reacts with phos sphate ion. . d) How many y electrons are present in the out ter shell of Barium. e) Will W the ele ements in the t group to the left of the beryll lium group p be more metallic m or less met tallic in cha aracter ? Ju ustify your answer. C: Give e suitable chemical c te erms for the e following g: [5] a) Which W forc ce of attrac ction involv ves in ionic compound d. b) Name N the charged c pa articles whi ich attract one o anothe er to form electrovale ent compounds. 1
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