Answer:
20 protons, 20 electrons, and 21 neutrons
Explanation:
The atomic number of an atom is the number of protons it has. If the atomic number is 20 then we know the atom has 20 protons.
•The mass number of an atom is the total number of protons and neutrons the atom contains. The mass number is 41 and the number of protons is 20, just subtract 20 from 41 and you will get the number of neutrons: 41 - 20= 21. The atoms has 21 neutrons.
•The number of electrons found in an atom is equal to the number of protons. The atoms has 20 protons which means it has 20 electrons.
So, the answer is:
20 protons, 20 electrons, and 21 neutrons
1) it explains about stability of an atom by including stationary state.
2) it explains tge quantization of energy.
3) it gives the concept of angular momentum of a revolving electron.
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
The answer is 0.375 mol of silver chromate
Answer:
The first question is 4
The second one is 1
Explanation:
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