[دنـــا]

في كم سؤؤؤؤال مو فـــاهمته بلييييييز احد يجااوبني ....؟ مررررة خايفة
(2) How many neutrons are present in an atom of silver which has a mass number of 108?
(a) 14
(b) 47
(c) 61*
(d) 108

What is the mass, in grams, of one copper atom?
A. 1.055  10-22 g
B. 63.55 g
C. 1 amu
D. 1.66  10-24 g
E. 9.476  1021 g



(12) The formula of stannic oxide is SnO2. The valence of Sn is
(a) +1
(b) +2
(c) +3
(d) +4*