Answer:
Explanation:
The Ce metal has electronic configuration as follows
[Xe] 4f¹5d¹6s²
After losing 4 electrons , it gains noble gas configuration ,. So Ce ⁺⁴ is stable.
Eu has electronic configuration as follows
[ Xe ] 4 f ⁷6s²
[ Xe ] 4 f ⁷
Its outermost orbit contains 2 electrons so Eu²⁺ is stable. Its +3 oxidation state is also stable.
Ce⁺²
Answer:
The corrext answer is E. make; break
Explanation:
In living organisms, the metabolism is either anabolic or catabolic where anabolic metabolism is energy consuming and catabolic metabolism is eneegy releasesing. It should however be noted that anabolic reaction builds or biosynthesize new mollecular structures while catabolic reaction breaks down complex structure bonds into simple structures
The braking down of bonds in catabolic reations realeses energy to sustain the anabolic rection process for the formation of new bonds
Answer:
3.74 x 10²² particles
Explanation:
Given parameters:
Mass of compound = 1.43g
Molar mass of compound = 23g
Unknown:
Number of particles of sodium = ?
Solution:
To find the number of particles of Na in the compound, we need to obtain the mass of sodium from the total mass given;
Mass of sodium = 
= 
= 1.43g
Now find the number of moles of this amount of Na in the sample;
Number of moles = 
= 
= 0.062mole
Now;
1 mole of substance = 6.02 x 10²³ particles
0.062 mole of substance = 0.062 x 6.02 x 10²³ particles
= 3.74 x 10²² particles
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days
Sorry I don’t exactly know I have exams rn I need points
