Answer:
At the molecular level, materials are held together by bonds, which act like springs for small displacements from the equilibrium spacing between neighboring atoms. Push the atoms close, the bond pushes back to keep them apart. Pull them apart, the bond pulls the atoms closer. For those small displacements, it acts like a spring
The speed of the wave will be related to the stiffness of of those springs - you compress the material - how quickly do all of those little springs rebound and push their neighboring atoms away, sending that wave of compression through the material.
Explanation:
<span>2 Nitrogen, 4 Hydrogen, 3 Oxygen
9 atoms per molecule.
NH4, ammonium (not to be confused with ammonia NH3) is a 1+ ion and NO3 is 1-.
</span>
A and C Im pretty sure :)
Metallic bonds! Hope this helps!! :))