Which statement best describes the atoms of the gas neon? A They slide past each other. B They move freely in all directions. C. They vibrate in place. D They are packed closely together.
The Correct Answer and Explanation is :
The correct answer is B: They move freely in all directions.
Explanation:
Neon is a noble gas, which means its atoms are chemically inert and do not readily form bonds with other atoms. It is also a monatomic gas, meaning that each neon atom exists independently rather than being part of a molecule. At room temperature and atmospheric pressure, the behavior of neon atoms can be explained by the kinetic molecular theory, which describes the behavior of gases.
According to the kinetic molecular theory:
- Gas particles are in constant, random motion. This means that the atoms or molecules of a gas move freely and independently, constantly colliding with each other and the walls of their container.
- There are no significant forces of attraction between the gas particles. This is especially true for noble gases like neon, as they have full electron shells and do not easily form bonds.
- The average kinetic energy of gas particles is directly proportional to the temperature. As the temperature increases, the neon atoms move faster and with greater energy.
In the case of neon:
- The atoms are not “packed closely together” (eliminating option D) because gases, in general, have much more space between particles than liquids or solids.
- The atoms do not “vibrate in place” (eliminating option C), as vibration in place is characteristic of solids, where particles are fixed in position but can vibrate due to thermal energy.
- The correct description is that the atoms move freely in all directions because in a gaseous state, the neon atoms have a lot of space to move and spread out.
This behavior is typical of gases, which have weak intermolecular forces and a high degree of freedom for their particles to move in all directions. This is why gases like neon expand to fill their containers completely and uniformly.