The chemical formula of sodium hydroxide is NaOH, and its molar mass is 40.01 g/mol. It is the alkali salt of sodium, and its structure is shown below:
It is an ionic compound consisting of sodium cation (Na+) and hydroxide (OH-) anion.
The actual number of atoms of each element present in the molecule of the compound is represented by the formula known as molecular formula.
Molar mass of the unknown compound = 223.94 g/mol (given)
Mass of each element present in the unknown compound is determined as:
- Mass of carbon,
:

- Mass of hydrogen,
:

- Mass of chlorine,
:

Now, the number of each element in the unknown compound is determined by the formula:

- Number of moles of
:

- Number of moles of
:

- Number of moles of


Dividing each mole with the smallest number of mole, to determine the empirical formula:


Multiplying with 2 to convert the numbers in formula into a whole number:
So, the empirical formula is
.
Empirical mass = 
In order to determine the molecular formula:
n = 
n = 
So, the molecular formula is:

A=Mass number=24
N=neutrons=13
Z=atomic number.
A=Z+N
24=Z+13
Z=24-13
Z=11
The atomic number is 11, and this atom is sodium.
Answer:

Explanation:
A compound must have a net charge of 0. The charges have to balance each other out and equal 0.
We have the compound sulfur trioxide with a chemical formula of SO₃.
Oxygen (O) has an oxidation state of -2, which means it will have a charge of -2 in the compound. However, note there is a subscript after the O in the chemical formula. Therefore, there are 3 oxygen atoms in the compound and each one has a charge of -2. The oxygen has an overall charge of -6 because 3*-2 = -6.
There is only one atom of sulfur (there is no subscript, so a 1 is implied). It has to balance out the -6 charge of the oxygen atoms, so it must be +6.
The oxidation number for sulfur is +6 in the compound sulfur trioxide.