CARNEGIE MELLON UNIVERSITY

09-105 Introduction to Modern Chemistry

Quiz #6

October 25, 2001

Name KEY (2 pts each)

Section /Instructor

H                                 He
Li Be                     B C N O F Ne
Na Mg                     Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac* Rf Db Sg Bh Hs Mt 110 111 112   114        
  La* Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu  
  Ac* Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw  

 

For each of the underlined elements below, indicate its oxidation number in the compound shown.

C2O3

O is -2 so two C's must add to +6 or the O.N. of C here is +3

(HO)ClO2

H is +1, each O is -2, then Cl must be +5 to give a neutral compound

Hg2Cl2

Cl would be -1 implying that Hg would be +1 in this compound

U3O8

If each oxygen is -2, three U's must add to 8*2=16 implying each U is +16/3

CaO2

Ca, an alkaline earth (Group II), has O.N. +2. The two O's must add to -2 or each O has an O.N. of -1