Question

What is a weak bond called?

Answer 1

Chemical bonds can be of different types. They are mainly formed when an electron is transferred or a pair of electrons are donated or shared between two atoms. Sometimes bonds can form when two atoms or ions come in the vicinity of other atoms or ions. They form a weak bond.

Complete answer:
The chemical bond which is formed when electrons are shared among two atoms is known as an ionic bond. There is an electrostatic force of attraction between the bonded atoms. For example the formation of NaCl.
The chemical bond which is formed when a pair of electrons are shared among two atoms is called a covalent bond. A covalent bond can be of three types. Single bond: When a single pair of electrons is shared among two atoms, Double bond: when two pairs of electrons are shared among atoms and Triple bond when three pairs of electrons are shared among two atoms. Compounds having covalent bonds are methane, ethene, ethyne etc.
Sometimes a chemical bond is formed when an atom donates a pair of electrons to the other and this type of bond is known as a coordinate bond or dative bond. An example of a compound having a dative bond is ammonium ion.
All these three types of bonds are ‘true bonds’ since they involve the transfer or sharing of electrons and the bonds bind atoms together. Among these bonds, the ionic bond is the weakest one.
Other forms of bonds that do not involve any electron transfer are hydrogen bonds and van der Waals force of attraction. Hydrogen bonds are formed among hydrogen and the electronegative atoms oxygen, nitrogen and fluorine. These are very weak bonds but they are stronger than van der waals force of attraction. Van der wall’s force of attractions is a soft bond which is a mild force of attraction among molecules and atoms.
Hence van der Waals attraction is the weakest bond among all.

Note:
Always remember that the ionic bond is the weakest bond among the ‘true bonds’ but if we consider all the bonds and molecular interactions, the van der Waals force of attraction is the weakest.