In one year old light can travel to how many km??
2 answers:
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Answer:
Explanation:
The question is asking to write the <em>isotopic symbol </em>of the form for the <em>sodium isotope with 13 neutrons</em>.
In general, the isotopic symbol in the given form shows:
- The element's chemical symbol: X
- A: mass number of the isotope, written as a superscript to the left of the element's simbol, and
A = number of protons + number of neutrons
- Z: atomic number of the isotope, written as a subscript to the left of the elements's symbol,
Z = number of protons
The atomic symbol of sodium is Na.
The atomic number, or number of protons, is the same for every isotope of the element, and you can find it in any periodic table. Tha atomic number of sodium is 11. Thus:
- Z = 11
The mass number is the number of protons plus neutrons, hence:
- A = 11 + 13 = 24
Now you can write the isotope symbol for the sodium isotope with 13 neutrons: