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.
Sc (neutral) [Ar] 3d1 4s2
Sc+ [Ar] 3d1 4s1
Sc2+ [Ar] 3d1
hope this helped!
In Chemistry, to better determine the position of a certain electron, quantum numbers are used. The four quantum numbers are n, l, m and s. In the given above of n= 4, the principal quantum number is 4 and this represents the overall relative energy in the orbital. This means that we are to find the maximum number of electrons in fourth main energy level and the answer is 32.
0.5 litres contain 1.1 moles
therefore 1 litre will have= 1*1.1/0.5
molarity=2.2M
Answer:
1st question: The moon is closer to Earth so it is easier to see and visit.
2nd question: The moon has a week/month cycle instead of a day/night cycle.
3rd question: The corona
Explanation:
