Unit cells.
They are the smallest group of atoms that take form of a crystal and can repeat in 3 dimensions.
Answer:
After 90 minutes 5.15625 g amount left from total of 165 g.
Explanation:
Given data:
Technetium-104 half life = 18.0 min
Total amount of sample = 165 g
Amount left after 90.0 min = ?
Solution:
First of all we will calculate the number of half lives passes.
Number of half lives = T elapsed / Half life
Number of half lives = 90 min /18.0 min
Number of half lives = 5
Amount left:
At time 0 = 165 g
At first half life = 165 g/ 2= 82.5 g
At 2nd half life = 82.5 g/2 = 41.2 g
At 3rd half life = 41.2 g/ 2 = 20.625 g
At 4th half life = 20.625 g/ 2 = 10.3125 g
At 5th half life = 10.3125 g /2 = 5.15625 g
Thus, after 90 minutes 5.15625 g amount left from total of 165 g.
The answer to your question is A
The advantage of using an orbital notation is that it shows the electron distribution in shells.
<span>Dot structures only show the valence electrons of an atom which are the electrons found at the outermost shell. The orbital notation gives a more detailed depiction of the electrons in each shell. This is most advantageous for atoms that have special cases. </span>
<span>Some examples of atoms that have special electronic configurations are copper and chromium. For example, copper is more stable when the 3d subshell is completely filled. This leaves the 4s subshell with only 1 electron. Chromium is also more stable when its s and d subshells are only half full. The orbital notation depicts these special cases, whereas the dot structure does not.</span>
