What is the main difference between an ionic and a covalent bond?
A Both bonds are the same, but named different to describe different atoms involved.
B One is the sharing of a pair of electrons, the other is the transfer of at least one electron.
C The electrons are traded between the two atoms and this keeps the atoms close.
D One involves electrons, the other does not involve any electrons.
E The electrons in both types of bonding undergo an exchange.
The correct answer and explanation is :
The correct answer is:
B. One is the sharing of a pair of electrons, the other is the transfer of at least one electron.
Explanation:
Ionic and covalent bonds are both types of chemical bonds that hold atoms together, but they form in different ways based on how electrons are handled between atoms.
- Covalent Bonds:
In a covalent bond, atoms share electrons in order to achieve a full outer shell of electrons (a stable configuration). This bond typically occurs between nonmetal atoms that have similar electronegativities, meaning they have a similar ability to attract electrons. The sharing of one or more pairs of electrons creates a stable relationship between the atoms. For example, in a water molecule (H₂O), the oxygen atom shares electrons with hydrogen atoms.
- Example: In a molecule of oxygen (O₂), two oxygen atoms share two pairs of electrons to form a double covalent bond.
- Ionic Bonds:
In contrast, ionic bonds involve the transfer of electrons between atoms. This bond typically occurs between a metal atom and a nonmetal atom, where the metal atom loses one or more electrons and the nonmetal atom gains those electrons. This transfer creates charged particles called ions (positively charged cations and negatively charged anions), which are held together by electrostatic forces of attraction.
- Example: In sodium chloride (NaCl), sodium (Na) loses one electron to become Na⁺, and chlorine (Cl) gains that electron to become Cl⁻. The oppositely charged ions attract each other, forming the ionic bond.
Key Differences:
- Electron behavior: In ionic bonds, electrons are transferred from one atom to another, while in covalent bonds, electrons are shared.
- Nature of the bond: Ionic bonds generally form between metals and nonmetals, while covalent bonds form between nonmetals.
- Electrical properties: Ionic compounds often conduct electricity in molten or dissolved form because of the movement of ions, whereas covalent compounds generally do not conduct electricity in any state.
Understanding these fundamental differences helps in predicting the properties of compounds formed by ionic and covalent bonds.