Answer: 20.2
Explanation:
Mass of isotope 1 = 20
% abundance of isotope 1 = 90.5% = 
Mass of isotope 2 = 22
% abundance of isotope 2 = 8.0% = 
Mass of isotope 3 = 23
% abundance of isotope 3 = 1.5% = 
Formula used for average atomic mass of an element :
![A=\sum[(20\times 0.905+(22\times 0.08)+(23\times 0.015]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%2820%5Ctimes%200.905%2B%2822%5Ctimes%200.08%29%2B%2823%5Ctimes%200.015%5D)
Therefore, the average atomic mass of the element is 20.2.
C is the answer i believe
Answer:
The pennies are NOT made of pure copper since the obtained density is 9.29 g/cm3 which is greater than the density of copper which is 8.96 g/cm3.
Explanation:
The valence electron configuration for antimony (Sb) is:
Sb = 5s²5p³5d⁰
In SbCl₅²⁻, antimony has a -2 charge i.e. it has 2 additional electrons
Sb²⁻ = 5s²5p⁵5d⁰
Following a two electron transition from p→d orbital we have:
Sb²⁻ = 5s²5p³5d²
There is a total of 5 unpaired electrons (3 in the p and 2 in the d) which can form five bonds with the 5 Cl atoms.
Thus the hybridisation of Sb in SbCl₅²⁻ is sp³d²
Lar mass of Ca<span> = 40.08 </span>grams/mole 77.4 g Ca<span> * ( 1 </span>mole Ca<span>/ 40.08 ... n = m / M 1mol </span>Ca<span>weights 40 gmol-1 n = 77,4 / 40 = 1.93 </span>mol<span>.</span>
