Question

The van der Waals attraction arises due to ___ induced dipoles in atoms.

Short answer

Induced dipoles.

Step-by-step solution

Understand the Concept of Van der Waals Forces

Van der Waals forces are intermolecular forces that arise from the interaction between molecules or atoms. These forces are usually weaker than covalent or ionic bonds and occur due to fluctuations in electron density.

Examine Induced Dipoles in Atoms

Atoms and molecules can have dipoles induced in them when their electron clouds are distorted. This distortion can be due to the presence of nearby charged particles or fluctuating electron clouds.

Connect Induced Dipoles to Van der Waals Forces

When the electron clouds of adjacent atoms influence each other, they can induce temporary dipoles. These induced dipoles cause an attraction between atoms, known as van der Waals attraction.

Key concepts

Induced Dipoles

Induced dipoles are temporary and occur when an external electric field causes distortion in the distribution of electrons around an atom or a molecule. This field can stem from neighboring charged particles or fluctuating electron clouds, leading to a temporary uneven electron distribution. This causes the atom or molecule to gain a temporary dipole moment.
The major characteristic of induced dipoles is that they are fleeting, lasting only as long as the external influence persists. They are crucial in the interactions that we recognize as van der Waals forces. For example, when two neutral atoms come close, their electron clouds affect each, inducing temporary dipoles that attract each other for a brief moment, resulting in van der Waals attraction. Understanding induced dipoles is vital for grasping how even neutral particles can exert forces on each other.

• Induced dipoles are temporary.
• Caused by external electric influences.
• Essential for creating van der Waals attractions.

Intermolecular Forces

Intermolecular forces are the forces that mediate interaction between molecules, including attraction or repulsion. These forces are electric in nature, although much weaker compared to covalent or ionic bonds. They dictate the behaviors and properties of substances, from boiling points to solubility. While several types exist, van der Waals forces are particularly noteworthy for their role in temporary attractions due to induced dipoles.
These van der Waals forces exemplify how weak interactions contribute to the complex behavior of molecules. Despite their strength being low in comparison to other types of bonds, they are crucial in non-covalent interactions, aiding in understanding phenomena like condensation and molecular recognition in biological systems. Their ability to form and break easily is vital in dynamic processes, such as protein folding or the way adhesives work.

• Intermolecular forces include van der Waals forces.
• Weaker than covalent or ionic bonds.
• Influence physical properties significantly.

Electron Density Fluctuations

Electron density fluctuations refer to the rapid and random changes in the position of electrons within an atom or molecule. These fluctuations are fundamental because they lead to the temporary dipoles that give rise to van der Waals forces. At any moment, the electrons within a cloud may concentrate more in one region over another, leading to an instantaneously created dipole that can influence neighboring atoms.
The key to these fluctuations is their spontaneity and unpredictability. Because the electron density isn't static, these small, momentary changes can induce dipole-dipole interactions even in nonpolar substances. This interaction is critical for understanding how nonpolar substances like noble gases liquefy under pressure or low temperatures.

• Fluctuations are random changes in electron positions.
• Responsible for induced dipoles.
• Key to understanding van der Waals attractions.