<u>Answer:</u> The amount of sample left after 20 years is 288.522 g and after 50 years is 144.26 g
<u>Explanation:</u>
We are given a function that calculates the amount of sample remaining after 't' years, which is:

Putting values in above equation:


Hence, the amount of sample left after 20 years is 288.522 g
Putting values in above equation:


Hence, the amount of sample left after 50 years is 144.26 g
<span>
Evaporation occurred between the reaction of the hydrochloric acid and the arsenic group because there is a formation of gas. A
liquid is cooled if condensation exceeds evaporation. This is because the cooling of the liquid decreases the kinetic energy of the
molecules. Their movement is being restricted by the colder temperature. The
molecules tend to be closer with each other. Also, because of their restricted
movement, the liquid may turn into solid due the colder temperature. An example
of this is the cooling of liquid water by placing it into the refrigerator into
solid water (ice).</span>
Is there an equation? I can't help if there's no equation involved.
Answer:
1s² 2s²2p³
Explanation:
If the atom has seven electrons, it is Element 7 (nitrogen).
In the Periodic Table, you count the electrons in all the subshells up to
No. 7.
In the first Period, you have filled the 1s level (2 electrons).
In the second Period, you have filled the 2s subshell (2 electrons) and put three electrons in the 2p subshell.
Thus, the electron configuration is
1s² 2s²2p³
Note how the superscripts tell you the number of electrons in each subshell: <em>2 + 2 + 3 = 7</em>.