Ionic bonding- the complete transfer of valence electron(s) between atoms and is a type of chemical bond that generates two oppositely charged ions. By losing those electrons, these metals can achieve noble-gas configuration and satisfy the octet rule. Similarly, nonmetals that have close to 8 electrons in its valence shell tend to readily accept electrons to achieve its noble gas configuration. Metals like sodium tend to lose electrons to achieve full valence shells, and nonmetals like chlorine tend to gain electrons. The process of gaining or losing electrons crates ions, and electrostatic forces bring the ions together to form compounds.

Ionic model:

Covalent bonding- describe the bonds in compounds that result from the sharing of one or more pairs of electrons

Water is an example of a covalent bond. It is polar.

Explanation of how periodic trends affect bonding:
Periodic trends affect bonding, because of how the elements are arranged on the periodic table. For example elements can be arranged by their electronegative, electron affinity, atomic radius, or ionization energy. Electronegative is the atoms ability to attract other bonded atoms. Electron affinity is an atoms ability to attract another atom. The atomic radius is the radius of an elements atom. Ionization energy is the energy it takes to remove an atom from another atom. Other periodic trends are when the attraction of the atoms for the pair of bonding electrons is different, this is polar