A small cylinder of helium gas used for filling balloons has a volume of 2.20 L and a pressure of 14300 kPa at 25 ∘C. Part A How
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Answer:
- <em>There are </em><u><em>14 protons</em></u><em> (Z) and </em>14 neutrons<em> (N) in a nucleus of the most common isotope of silicton.</em>
Explanation:
The notation of the <em>most common isotope of silicon</em> is:
The superscript, 28, to the left of the chemical symbol, Si, is the mass number, usually identified with the symbol A, and it is the sum of the protons and neutrons.
The subscript, 14, to the left of the chemical symbolr, Si, is the atomic number, Z, which is the number of protons.
Then, you have this equation:
- mass number = number of protons + neutrons, or, in symbols:
- A = Z + N
The number of protons is the same for any isotope of the same element. This is, all the isotopic forms of silicon have the same number of prtons: 14
The number of neutrons is determined from the equation A = Z + N, solving for N:
- N = A - Z = 28 - 14 = 14.
Hence, the most common isotope of silicon has 14 protons and 14 neutrons.
The atomic mass<span> of an element is a weighted average of its </span>isotopes<span> in which the sum of the abundance of each isotope is equal to 1 or 100%.
</span><span>Let fraction of N-15 be x
then fraction of N-14 = 1-x
</span>
<span>Formula for Calculating Isotope:
</span>
on calculation:
x = <span>0.006403
so, % = 0.006403 x 100 = 0.6403 %<span>
</span></span>
</span><span>Let fraction of N-15 be x
then fraction of N-14 = 1-x
</span>
<span>Formula for Calculating Isotope:
</span>
on calculation:
x = <span>0.006403
so, % = 0.006403 x 100 = 0.6403 %<span>
</span></span>