Name: intermolecular forces in polar solutions
Uploaded: 2026-06-01T06:28:22.893Z
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North Carolina K-12 Science Standard Course of Study

9-12

Chemistry

Matter and its Interactions

PS.Chm.3.2

Van der Waals Interactions

Van der Waals interactions are weak intermolecular forces that arise from electrostatic interactions between atoms and molecules that are electrically neutral overall.These interactions are broadly classified into three types: London dispersion forces, dipole&#x2013;dipole forces, and dipole-induced dipole forces.All molecules, even nonpolar ones, have temporary partial charges.Due to the varying distribution of electrons, a higher electron density in one region of the electron cloud results in an instantaneous dipole or a temporary dipole.This then causes another instantaneous dipole in the neighboring molecule. The domino effect of dipoles gives rise to weak intermolecular attractive forces, which exist between all molecules, whether polar or nonpolar.These interactions between temporary dipoles are called London dispersion forces.Dipoles in polar molecules like water electrostatically interact through dipole-dipole forces.Dipole-induced dipole forces happen when a polar molecule, like water, disturbs the electronic arrangement of a non-polar molecule, like diatomic oxygen, and causes a dipole.All these interactions are attractive when the atoms are close enough for their electron clouds to just contact. If the atoms get any closer, these forces become repulsive.

van der waals interactions

Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion&#x2013;dipole, dipole&#x2013;dipole, and dispersion forces, collectively known as van der Waals forces.Polar molecules have a partial positive charge on one end and a partial negative charge on the other end of the molecule, creating a dipole. In a polar molecule like water, the more electronegative oxygen atom bears the partial negative charge, and the less electronegative hydrogen atom carries the partial positive charge. The water molecules are attracted to each other because of the positive end of one water molecule and the negative end of another. This attractive force is called a dipole&#x2013;dipole attraction.An ion&#x2013;dipole force is the electrostatic attraction between an ion and a dipole. These forces are common in solutions and play an important role in the dissolution of ionic compounds in water. When an ionic compound like KCl is added to a polar solvent like water, the ions in the solid separate and disperse uniformly. Ion&#x2013;dipole forces attract the positive end of the polar water molecules to the negative chloride ions at the surface of the solid, and they attract the negative ends to the positive potassium ions. The water molecules surround individual K+ and Cl- ions, reducing the strong interionic forces that bind them together in a solid and dissolving them. The strength of ion&#x2013;dipole interactions is directly proportional to i) the charge on the ion and ii) the magnitude of the dipole of polar molecules.Dispersion forces are present in all condensed phases, regardless of the nature of the atoms or molecules composing the substance. These attractive forces are also called London dispersion forces in honor of German-born American physicist Fritz London who first explained them in 1928. The electrons of an atom or molecule are in constant motion at any moment in time, and an atom or molecule can develop a temporary, instantaneous dipole if its electrons are distributed asymmetrically. The presence of this dipole can, in turn, distort the electrons of a neighboring atom or molecule, producing an induced dipole. These rapidly fluctuating, temporary dipoles result in a relatively weak electrostatic attraction between the species&#x2014;a so-called dispersion force. Dispersion forces are relatively weak and become significant only when the molecules come very close. Larger and heavier atoms and molecules exhibit stronger dispersion forces than smaller and lighter ones.This text is adapted from <a href="https://openstax.org/books/chemistry-2e/pages/10-introduction">Openstax, Chemistry 2e, Chapter 10: Liquids and Solids</a>.

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Learn by watching this video about Van der Waals Interactions and Temporary Dipoles at JoVE.com

intermolecular forces in polar solutions

Intermolecular forces are the attractions and repulsions that act between atoms and molecules. These electrostatic forces come from particles with permanent, partial, or temporary charges. For neutral atoms and molecules, the main types are ion-dipole, dipole-dipole, and dispersion forces, which are together called van der Waals forces.

Polar molecules have a partial positive end and a partial negative end. That separation of charge creates a dipole. In water, oxygen is more electronegative than hydrogen, so oxygen carries the partial negative charge and hydrogen carries the partial positive charge. Water molecules attract each other because the positive end of one molecule is drawn to the negative end of another. This is a dipole-dipole attraction.

Ion-dipole forces are the attraction between an ion and a dipole. They are common in solutions and help ionic compounds dissolve in water. When KCl is added to polar water, the ions separate and spread out through the liquid. Water molecules line up around the K+ and Cl- ions. The positive ends of water are attracted to chloride ions, and the negative ends are attracted to potassium ions. This surrounding shell weakens the strong forces holding the solid together and allows it to dissolve. The strength of ion-dipole interactions depends on the charge on the ion and the size of the dipole in the polar molecule.

Dispersion forces are present in condensed phases no matter what atoms or molecules make up the substance. They are also called London dispersion forces, named for Fritz London, who explained them in 1928. Electrons are always moving, so an atom or molecule can briefly develop a temporary dipole when the electrons are unevenly spread out. That dipole can distort a nearby particle and create an induced dipole. The weak attraction between these changing dipoles is a dispersion force. These forces matter most when molecules are very close. Larger and heavier atoms and molecules usually have stronger dispersion forces than smaller and lighter ones.

Intermolecular Forces in Polar Solutions

the periodic table and organismal elements

the-periodic-table-and-organismal-elements

Periodic Table Basics for Living Things

The periodic table helps explain which elements living things need and how those elements are related. Elements are the smallest units of matter that cannot be broken down further by chemical processes. There are 118 known elements, but not all occur naturally, and even fewer are essential for life. Living matter is made mostly of carbon, nitrogen, hydrogen, and oxygen. Together, these elements make up most of the human body and are also found in all life on Earth. Smaller amounts of calcium,...

atomic structure

Atoms and Their Subatomic Particles

Atoms are the smallest units of elements, and they make up all matter. Each atom contains three subatomic particles: protons, neutrons, and electrons. These particles give an atom its mass and its charge. The idea that matter is made of tiny particles goes back to Democritus, a Greek philosopher around 450 B.C. He used the word atomos, which means “indivisible.” The idea was not accepted at the time, but it returned many centuries later. In the 19th century, John Dalton proposed an atomic...

isotopes

Atomic Mass and Isotope Basics

Atomic mass and isotopes are linked by the number of protons and neutrons in an atom. The number of protons sets an element’s atomic number, or Z. For example, every atom with eight protons is oxygen. Atoms of the same element can still differ because they can have different numbers of neutrons. The mass number, or A, is the total of protons and neutrons. Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have several isotopes. Carbon-12, carbon-13,...

electron behavior

Electron Shells and Valence Electrons

Electrons are negatively charged subatomic particles that occupy regions around the positively charged nucleus of an atom. Their location is linked to energy levels called shells. They are also grouped into sub-shells and orbitals within each shell. An electron’s shell shows its general energy level. Electrons closer to the nucleus have less energy, while electrons farther away have more energy. The sub-shell gives a more exact location and energy level. An orbital is the shape of the region...

electron orbital model

Electron Orbitals and Energy Levels

Electron orbitals show where electrons are most likely to be found around the atomic nucleus. They also help explain energy levels, orbital shapes, and three-dimensional orientation. In an atom, electron location is described first by a shell, or principal energy level. It is then described by a subshell within that shell and by the individual orbitals inside each subshell. The first shell is closest to the nucleus. It has only one subshell and one spherical orbital, called the 1s orbital.

covalent bonds

Electronegativity and Covalent Bond Polarity

Covalent bonds form when two atoms share electrons to fill their valence shells. The way those shared electrons are pulled depends on electronegativity, which is an atom’s ability to attract electrons in a bond. When atoms have similar electronegativities, they form nonpolar covalent bonds. When their electronegativities differ, the bond is polar because the electrons are shared unevenly. The number of covalent bonds an atom can make depends on its valence electrons. Oxygen has six valence...

ionic bonds

Ionic Compounds and Electrolytes

Ionic compounds form when atoms gain or lose electrons to reach a more stable electron configuration. The charged particles that result are called ions. Ionic bonds are electrostatic attractions between oppositely charged ions. The most reactive elements include those with one valence electron, such as potassium, and those that need one more valence electron, such as chlorine. Ions that lose electrons become positive cations. Ions that gain electrons become negative anions. Cations and anions...

hydrogen bonds

Hydrogen Bonds in Water

Hydrogen bonds in water are weak attractions between atoms that are already part of other chemical bonds. One atom is electronegative, such as oxygen, and carries a partial negative charge. The other is a hydrogen atom that is bonded to another electronegative atom and has a partial positive charge. These attractions form because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom like oxygen or nitrogen. The electrons in that bond are shared unequally.

Intermolecular forces are the attractions and repulsions that act between atoms and molecules. These electrostatic forces come from particles with permanent, partial, or temporary charges. For neutral atoms and molecules, the main types are ion-dipole, dipole-dipole, and dispersion forces, which are together called van der Waals forces. Polar molecules have a partial positive end and a partial negative end. That separation of charge creates a dipole. In water, oxygen is more electronegative...

elements and compounds

Elements, Compounds, and Bonding

Elements and compounds are the two main kinds of pure substances. A pure substance contains only one kind of matter. An element contains only one type of atom. A compound contains two or more types of atoms joined by a chemical bond. Elements can be atomic or molecular, depending on their basic units. They are unique forms of matter with specific chemical and physical properties. Ordinary chemical reactions cannot break an element into a smaller substance. There are 118 elements, but only 98...

molecular shapes

Electron Geometry and Lone Pairs

Electron geometry and lone pairs help explain why molecules take specific shapes. The arrangement of electron groups around a central atom controls the molecular geometry. Valence electrons form bonding pairs, which sit mainly between bonded atoms, or lone pairs, which belong to one atom only. Electron pairs in the valence shell spread out to reduce repulsion. They do this by maximizing the distance between one another. A diatomic molecule has two regions of electron density, and these are...

pH Scale in Everyday Solutions

pH measures how acidic or basic a water-based solution is. It depends on the concentration of hydronium ions, H3O+, in the solution. In one liter of pure water at neutral pH, there are 1×10−7 moles of hydronium ions. Because hydronium ion levels can vary over a very wide range, measuring pH directly in moles is not practical. The pH scale converts hydronium ion concentration into a negative logarithm. Pure water has a pH of 7 and is neutral. Most solutions fall between 0 and 14, but some, such...

chemical reactions

Atoms, Bonds, and Chemical Reactions

Chemical reactions rearrange atoms to form new substances. In a reaction, the starting materials are called reactants, and the new substances are called products. The atoms stay the same type and number, but their bonds change, so the substances become different compounds. During a chemical reaction, bonds between atoms break and form again. This means the shared electrons are rearranged. Some reactions happen on their own, while others need an energy source such as heat or light. In biology,...

redox reactions

Electron Transfer in Redox

Redox reactions are chemical reactions that involve electron transfer between atoms or molecules. When one particle gains electrons, another must lose them at the same time. That is why oxidation and reduction always happen together. The two roles in a redox reaction are linked. The atom that is oxidized acts as the reducing agent, or reductant. The atom that is reduced acts as the oxidizing agent, or oxidant. A simple way to remember the ideas is OIL-RIG, which means oxidation is losing...

cohesion

Water Molecules and Surface Tension

Water molecules stick to each other through cohesion. Water is neutral overall, but it is a polar molecule. The oxygen atom in one water molecule has a partial negative charge, and it can bind with a hydrogen atom that has a partial positive charge in another water molecule. This forms a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules, and these bonds give water its cohesive nature. Cohesion helps water form droplets on a surface. Water does not...

adhesion

Water Climbing by Adhesion

Water can climb or stick to surfaces because of adhesion, which is the attraction between different kinds of molecules. In water, this is easy to see on polar surfaces such as glass or cellulose in plants. The positive hydrogen side of water is more attracted to the negative oxygen in silica than to nearby water molecules. This attraction helps explain capillary action. If a narrow glass tube is placed in a beaker of water, water molecules attach to the tube’s surface and the water level rises.

states of water

Water Phase Changes and Ice Density

Water changes between solid, liquid, and gas states as temperature and molecular motion change. In this lesson, the focus is on how water freezes, melts, vaporizes, and returns to liquid or solid form. The balance between intermolecular forces, which pull molecules together, and kinetic energy, which pushes them apart, controls each state. Water freezes when intermolecular forces become stronger than kinetic energy. Unlike most substances, ice is less dense than liquid water. This happens...

specific heat

How Specific Heat Affects Temperature

Specific heat capacity describes how much energy a substance needs to rise by 1 degree Celsius for each gram. It is often written with calories, grams, and degrees Celsius, but it can also be shown in joules, kilograms, and Kelvin. For water, 1 gram needs 1 calorie to increase by 1°C, which is also written as 1 cal/g-°C or 4186 J/kg/K. Water has a high specific heat capacity, so it takes in a large amount of heat before its temperature changes much. It also gives off a lot of heat when it...

vaporization

Vaporization, Boiling, and Evaporation

Vaporization changes a liquid into vapor when temperature adds enough kinetic energy to overcome intermolecular forces. It is a surface phenomenon, which means it starts at the liquid’s surface. The energy needed to vaporize a set amount of liquid at a given pressure and constant temperature is called the heat of vaporization. Water shows this process clearly. When liquid water is vaporized, it becomes steam. One way this happens is boiling, which occurs when vapor bubbles form beneath the...

solvents

Water as a Biological Solvent

Water acts as a biological solvent in many living systems. A solvent is a substance, usually a liquid, that dissolves another substance called a solute. When a solvent and a solute mix, they form a solution, which is a uniform mixture of both parts. Water is called a universal biological solvent because its polar structure helps it dissolve many other polar compounds. Polarity means that one side of the molecule has a slight positive charge and the other side has a slight negative charge.

carbon skeletons

Carbon Backbones in Biomolecules

Carbon backbones give biological molecules their structure and flexibility. Living things are built from macromolecules that contain carbon atoms, and organic compounds are defined by a carbon backbone. Carbon is tetravalent, so each carbon atom can bond with four other atoms. Its valence electrons are stable, so carbon rarely becomes an ion. As carbon chains get longer, they can form ring structures, double bonds, and branching side chains. Carbon-carbon bonds create the carbon skeleton.

key terms and concepts

Explore how ion-dipole, dipole-dipole, and dispersion forces help water attract molecules and dissolve ionic solids like KCl in solutions.

Intermolecular Forces in Polar Solutions | JoVE K12

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Louisiana Student Standards for Science

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Matter And Its Interactions

HS-PS1-1

HS-PS1-3

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Motion And Stability: Forces And Interactions

HS-PS2-6

Tennessee Academic Standards

Physics

Motion and Stability: Forces and Interactions

PHYS.PS2.8

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PH.9

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Texas Essential Knowledge and Skills

CHEM.7

CHEM.7.D

Alabama Course of Study Science

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From Molecules to Organisms: Structures and Processes

9-12.B.1.4.b

9-12.C.2.2.g

Next Generation Science Standards

Physical Science

Matter and Its Interactions

HS-PS1-12

Florida Department of Education

SC.912.P.8

SC.912.P.8.6

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South Carolina College and Career Ready Science Standards

C-PS1-3.

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Scientific Laws and Theories

Scientific Laws

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Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

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The Aufbau Principle and Hund's Rule

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Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

Use models to explain how electrons are distributed in atoms.

PS.Chm.1.3

Periodic Classification of the Elements

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The Periodic Table

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Atomic Mass

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Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

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PS.Chm.2.1

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Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

PS.Chm.2.2

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Chemical bonding theories were pioneered by American chemist Gilbert&nbsp;N. Lewis. He developed a model called the Lewis model to explain the type and ...

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Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a ...

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Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

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An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

PS.Chm.3.1

Analyze the structure of atoms and isotopes.

Intermolecular Forces in Polar Solutions

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