the Empirical formula of the compound is calculated as follows
find the moles of each element
moles = mass/molar mass
that is Magnesium= 0.564 g /24 g/mol = 0.0235 moles
For oxygen = 0.376 g /16 g/mol= 0.0235 moles
find the mole ratio by dividing both moles of by 0.0235 moles
magnesium = 0.0235/0.0235= 1mole
oxygen= 0.0235 /0.0235= 1mole
therefore the empirical formula = MgO
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:
The mass number is the number of protons plus neutrons, hence:
Now you can write the isotope symbol for the sodium isotope with 13 neutrons:
