Answer: The atomic weight of silver is 107.87 amu
Explanation:
Mass of isotope silver-107 = 106.91 amu
% abundance of isotope silver -107 = 51.84% = 
Mass of isotope silver-109 = 108.90 amu
% abundance of isotope silver-109 = 48.16% = 
Formula used for average atomic mass of an element :
![A=\sum[(106.91\times 0.5184)+(108.90\times 0.4816)]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%28106.91%5Ctimes%200.5184%29%2B%28108.90%5Ctimes%200.4816%29%5D)
Thus atomic weight of silver is 107.87 amu
The population density is 47 people/km^2..
<em>Step 1</em>. Calculate the <em>surface area of Earth</em>.
<em>d</em> = 12 700 km; <em>r</em> = 6350 km
<em>A</em> = 4π<em>r</em>^2 = 4π × (6350 km)^2 = 5.067 × 10^8 km^2
<em>Step 2</em>. Calculate the <em>habitable surface area</em>.
Habitable area = 5.067 × 10^8 km^2 total × (30 km^2 habitable/100 km^2 total) = 1.520 × 10^8 km^2 habitable
<em>Step 3</em>. Calculate the <em>population density
</em>
Population density = 7.1 × 10^9 people/1.520 × 10^8 km^2 = 47 people/km^2
The atomic number is the same as proton number. And the atomic mass is
equal to the sum of protons and neutrons. So the neutrons in the atom of
this element is 10.
