Question

give a brief description of the following

a. how do ionic compounds gain their octet to become stable?

b. how do covalent compounds gain their octet to become stable

Answer 1

a. Ionic bonds are formed through the exchange of valence electrons between atoms, typically a metal and a nonmetal. The loss or gain of valence electrons allows ions to obey the octet rule and become more stable. Ionic compounds are typically neutral. Therefore, ions combine in ways that neutralize their charges.

In Ionic Compounds there is complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic compounds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion. Ionic bonds require an electron donor, often a metal, and an electron acceptor, a nonmetal.

in ionic compound ,Ionic bonding is observed because metals have few electrons in their outer-most orbitals. 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 their valence shells tend to readily accept electrons to achieve noble gas configuration. In ionic bonding, more than 1 electron can be donated or received to satisfy the octet rule. The charges on the anion and cation correspond to the number of electrons donated or received. In ionic bonds, the net charge of the compound must be zero.In this way ionic compounds show stability by following the octet rule.

b. Covalent Compounds formed when electrons are shared between two atoms . A Covalent bond occur between two non-metal .

The octet rule is important in covalent bonding because sharing electrons gives both atoms a full valence shell.

All atoms strive to achieve a full valence shell, just like the noble gases. This is the most stable electron arrangement.

If atoms can’t achieve a full outer shell by transferring electrons, they resort to sharing. In this way, each atom can count the shared electrons as part of its own valence shell. This sharing of electrons is covalent bonding.

For example, an oxygen atom has six electrons in its valence shell. The most the shell can hold is eight. Two oxygen atoms can share their valence electrons as shown below.