Molecular Mass Of Na

Sodium (Na) is a chemical element with the atomic number 11. Its atomic mass, as listed on the periodic table, is approximately 22.99 u (unified atomic mass units). This value represents the average mass of sodium atoms, taking into account the natural abundance of its isotopes.

Breakdown of Sodium’s Molecular Mass

1. Atomic Mass of Sodium (Na):

   • Sodium has one naturally occurring isotope, Na-23, which accounts for nearly 100% of its natural abundance.
     
   • The atomic mass of Na-23 is 22.989769 u.
     

2. Molecular Mass Consideration:

   • Sodium is a monatomic element, meaning it exists as individual atoms (Na) rather than molecules.
     
   • Therefore, the molecular mass of sodium is equivalent to its atomic mass: 22.99 u.
     

Practical Applications of Sodium’s Mass

• Chemical Reactions: Knowing sodium’s atomic mass is crucial for stoichiometric calculations in chemical reactions.
  
• Molar Mass: The molar mass of sodium (mass of one mole of Na atoms) is 22.99 g/mol, which is used in laboratory measurements and formulations.
  
• Isotopic Studies: While Na-23 is the dominant isotope, trace amounts of radioactive Na-22 (half-life: 2.6 years) are used in medical imaging and research.
  

Calculation Example

To find the mass of a specific number of sodium atoms:
[ \text{Mass (g)} = \text{Number of atoms} \times \frac{\text{Atomic mass (g/mol)}}{N_A} ]
Where (N_A) (Avogadro’s number) = (6.022 \times 10^{23} \, \text{atoms/mol}).

For example, the mass of (10^{22}) sodium atoms:
[ \text{Mass} = 10^{22} \times \frac{22.99 \, \text{g/mol}}{6.022 \times 10^{23}} \approx 3.82 \, \text{g} ]

Key Takeaway

The molecular mass of sodium (Na) is 22.99 u, reflecting its atomic mass due to its monatomic nature. This value is fundamental in chemistry for calculations involving reactions, stoichiometry, and molar concentrations.