Answer: 28.1 amu
Explanation:
Mass of isotope 1 = 27.98 amu
% abundance of isotope 1 = 92.21% = 
Mass of isotope 2 = 28.98 amu
% abundance of isotope 2 = 4.70% = 
Mass of isotope 3 = 29.97 amu
% abundance of isotope 2 = 3.09% = 
Formula used for average atomic mass of an element :

![A=\sum[(27.98 )\times 0.922+(28.98)\times 0.047+(29.97)\times 0.0309]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2827.98%20%29%5Ctimes%200.922%2B%2828.98%29%5Ctimes%200.047%2B%2829.97%29%5Ctimes%200.0309%5D)

Therefore, the average atomic mass of silicon is 28.1 amu
Answer: B yeah I'm pretty sure
Answer:
The answer is D- make sure you give good rate
It is True because in the periodic table of elements, there are seven horizontal rows of elements called periods. The vertical columns of elements are called groups, or families.
Hey there!
<span>Energy that flows from an object with a higher temperature to an object with a lower temperature is
Answer: Heat energy
Hope this helps
Have a great day (:
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