Are all bonds chemical, since we’re talking about atomic interactions, but the distinction is made upon the strength and depth of the bond? And what does that mean, exactly?
Matter is made up of molecules, which are atoms bound together by electrical forces, which can be classified into 5 types: ionic, covalent, metallic, Van der Waals and hydrogen bonds.
These bonds can be classified into 2 groups: the shared-electron, including covalent and metallic and hydrogen bonds, which would be chemical bonds, and the unshared or closed-shell interaction of ionic and Van der Waals bonds, or physical bonds.
An example of an ionic bond is sodium chloride, where Na+ shares an electron with Cl-. The covalent bond, such as the sharing of a pair of electrons between two Cl- ions to produce Cl2, results in a very stable bond and is the strongest of all chemical bonds. Water is another example of a covalent bond The hydrogen bond is a low-energy electrostatic bond where hydrogen serves as a bridge between two atoms. Metallic bonding can be envisioned as a collection of positively charged electrons immersed in a cloud of valence electrons. Van Der Waals forces hold together neutral molecules with a weak electrical force. A molecule distorts weakly, forming a positively charged end and a correspondingly negatively charged opposite end. A similar effect is induced in neighboring molecules and propagates throughout the entire structure. This bond is temporary and effective only over short distances. 104
An example would be Gecko lizards climbing up flat surfaces such as walls and roofs, thanks to the force of attraction between their footpads and the surface.
A chemical bond between two substances results in a new chemical compound, with its own properties. A physical bond does not. Take for example the magnetic bond between a magnet and your fridge. It does not produce a new magnet-fridge entity. Magnetism itself is caused by the motion of electric charges in the atoms of magnetic materials, whose particularity is that their electrons’ charges don’t cancel each other out, but rather all spin in the same direction, creating a magnetic field that is able to attract other ferromagnetic metals and attract or repel other magnets.
Another example of a physical bond is gravity. You could say that “you” and “Earth” are bonded together somehow, since you don’t fall off Earth. According to <PERSON>, it’s because each particle of matter attracts every other particle of matter in the Universe with a force that is a function of mass and distance. The great mass of Earth and the short distance create a strong enough bond so you remain “bonded”, yet distinct.
Another bond which is deemed physical is the formation of metallic alloys, such as brass, which is 60% copper and 40% zinc and exhibits different properties than either copper or zinc, yet is not linked at the chemical level. This seems to contradict the definition of a physical bond!
The broad lines of the distinction between physical and chemical bonds are clear, but when you get down to the fine print or the actual unequivocal explanation of how things stick together, scientists still argue… 104