Answer:
D.
Explanation:
Bohr's model represented electrons in their respective e⁻ shells. Only D fits the description.
Be, B, C, N (going from smallest to biggest)
Answer:
They are so small that they barely make up any of the mass of the atom, and they are so miniscule that during Rutherford 's Gold foil experiment ,they didn't even react with the alpha particles. They circle the nucleus on a ring. shown through Rutherford Atomic Model
hope it helps you
Answer: It will take 6.93 sec for tracer concentration to drop by 50% and 13.9 sec for tracer concentration to drop by 75%
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = age of sample
a = let initial amount of the reactant = 100 g
a - x = amount left after decay process
a) for tracer concentration to drop by 50%
a - x = amount left after decay process
= 50

It will take 6.93 sec for tracer concentration to drop by 50%
b) for tracer concentration to drop by 75 %
a - x = amount left after decay process
= 25
It will take 13.9 sec for tracer concentration to drop by 75%.
The electron configuration of Zr (AN 40) is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d2 5s2