19. Bonds in solids – ionic, covalent, hydrogen and van der Waals (5p.)

Question 1

Ionic bonding

Answer 1

The bonding between a non-metal and metal that occurs when charged atoms attract is called ionic bonding. This happens after a metal atom loses one or more of its electrons to the non-metal atom. This makes the bond stronger and harder to break. When this happens, the metal becomes a positive cation and the nonmetal becomes a negative anion. Ex. NaCl (1à7)

Question 2

Covalent Bonding

Answer 2

Covalent bonding is the sharing of electrons between atoms. This type of bonding occurs between two atoms of the same element or if the elements are close to each other in the periodic table. This bonding occurs primarily between non-metals, however, it can also be observed between non-metals and metals.

• The above two bondings are called strong bonds – their bonding energy is greater than 1 eV.

• There are also weak bonds, with bonding energies lower than 1 eV.

Question 3

Hydrogen bond

Answer 3

A hydrogen bond is a weak type of force that forms a special type of dipole-dipole attraction, which occurs when a hydrogen atom bonded to a strongly electronegative atom exists in the proximity of another electronegative atom with a lone pair of electrons. These bonds are generally stronger than ordinary dipole-dipole and dispersion forces, but weaker than true covalent and ionic bonds. Typical bonding energies are smaller than 0.5 eV.

Question 4

Van der Waals

Answer 4

Van der Waals forces are the weak forces, which contribute to intermolecular bonding between molecules.