Answer :

molar mass Na = 23g/mol
46g = 456/2 = 2mol
1mol = 6.022*10^23 atoms
2mol = 2*6.022*10623
= 1.204*10^24 atoms
First step, is to find the Molar Mass.
If you go to the periodic table, the Molar Mass of the Sodium Na is 23g/mol

Second Step, you convert from grams to moles.
number of Mole = mass of sodium / molar mass = [tex] \frac{46}{23} = 2 mol[/tex]

Third Step, you find the number of atoms.
As We know, Avogadro said that the number of atoms in 1 mole is about [tex]6.022 * 10^{23}[/tex].
You use the Rule of three and you find the number of atoms!
1 mole = [tex]6.022 * 10^{23}[/tex] atoms
2 mole = x atomes
x = 2 * ( [tex]6.022 * 10^{23}[/tex] )
x= [tex]12.044 * 10^{23}[/tex] atomes

So, there is [tex]12.044 * 10^{23}[/tex] atoms of Sodium Na in 46g of Solution.

Hope this Helps! :D