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Intermolecular forces are collective forces in organic chemistry that cause atoms and molecules to stick together and interact; therefore, they are electrostatic in nature. The collective strength of these electrostatic interactions can affect a compound's physical properties, like melting and boiling points, density, refractive index, solubility, and others.

Almost all atoms and molecules interact through intermolecular forces, an inherent property resulting from the presence of electrons. 

Isomers are molecules with the same molecular formula; that is, they have the same atoms in exact numbers (or the same molar masses); however, they still differ in their structures.  

These differences or structural variations arise due to the atom’s attachment styles. 

An atom may connect differently, each time having different set of neighbors by bond or in space. 

Ion is different from an atom since an atom is an electrically neutral specie with an equal number of positive protons and negative electrons.

Isotopes are a group of atoms belonging to an element with the same atomic number but a different mass number. Such a group of atoms have the same number of protons in their nuclei but differ only in the number of neutrons.

For example, the Oxygen atom has three isotopes – ¹⁶O, ¹⁷O, and ¹⁸O. All three isotopes have 8 protons; however, the number of neutrons is 8 in ¹⁶O, 9 in ¹⁷O, and 10 in ¹⁸O.

An atom or group of atoms that can pull the bond electrons towards itself or push the bond electrons from itself and decreasingly transmit the effect along the sigma (σ) bonds of the carbon chain inducing permanent polarization in the molecule. Such an effect is called the Inductive effect.

Few substances like gum, starch, gelatin, rubber have an inherent or a natural tendency to form colloidal sol on direct mixing with a suitable dispersion medium and are called intrinsic colloids. As they are solvent loving, they are also known as lyophilic colloids.