1.2*10^24# atoms of chlorine
Explanation:
Chlorine gas (#Cl_2#) has two atoms of elemental chlorine in a molecule, so:
#1# mol of #Cl_2# have #6*10^23# molecules of #Cl_2#
#1# molecule of #Cl_2# have #2# atoms per molucule
Then #2*6*10^23 = 1.2*10^24# atoms of chlorine in a mol of chlorine gas
Answer: (E) 300 bq
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.
Half life is represented by 
Half life of Thallium-208 = 3.053 min
Thus after 9 minutes , three half lives will be passed, after ist half life, the activity would be reduced to half of original i.e. 
, after second half life, the activity would be reduced to half of 1200 i.e. 
, and after third half life, the activity would be reduced to half of 600 i.e. 
,
Thus the activity 9 minutes later is 300 bq.
Answer:
Bonding in chemistry is known as chemical bonding which means the interaction or attraction between molecules.
Chemical bonds are of different type such as ionic, covalent, hydrogen, and metallic. Ionic bonds are formed by the transfer of valence electron from one atom to other and there is unequal distribution of electrons between two or more atoms. Ionic bonds forms two oppositely charges ions positively charged (loses electron) or negatively charged (gains electron).
Covalent bond are the strong chemical bonds that form due to equal sharing of electron pairs between atoms. They form a stable element and have stable attraction or repulsive forces.
Molar mass Li2CO3 = 73.89 g/mol
Molar mass Li = 6.94g/mol Li = 6.94*2 = 13.88g
% LI = 13.88/73.89*100 = 18.78% perfectly correct.
