Chemical Bonds and Atomic Stability

Types of Chemical Bonds

• A chemical bond is the union of two atoms, which can be the same or different, with the purpose of becoming stable.

Atomic Stability

• According to Lewis, atoms are stable when they have 8 electrons in their valence shell, except for hydrogen and helium, which are stable with 2 electrons.

Types of Chemical Bonds

• There are three types of chemical bonds: ionic, covalent, and metallic.

Ionic Bond

• An ionic bond occurs when a metal atom bonds with a non-metal atom.
• The difference in electronegativities between the atoms is greater than 1.7.
• One of the atoms loses an electron, which is attracted by the more electronegative atom.
• Example: sodium chloride (NaCl), where sodium loses an electron to chlorine.

Covalent Bond

• A covalent bond occurs when two non-metal atoms bond.
• The characteristic of a covalent bond is that neither atom loses or gains an electron, but instead, they share electrons.
• There are three types of covalent bonds: non-polar, polar, and coordinate.

Non-Polar Covalent Bond

• A non-polar covalent bond occurs when two identical atoms bond.
• Example: hydrogen molecule (H2), where two hydrogen atoms share electrons to become stable.

Polar Covalent Bond

• A polar covalent bond occurs when two different non-metal atoms bond.
• The difference in electronegativities between the atoms is greater than zero but less than 1.7.
• Example: water molecule (H2O), where oxygen attracts the electrons from hydrogen to complete its octet.

Metallic Bond

• A metallic bond occurs when metal atoms bond with each other.
• Metal atoms are bonded together, forming a "sea of electrons" that allows metals to conduct electricity, heat, and have a characteristic luster.

Chemical Bonds

• Chemical bonds form to achieve atomic stability, which is attained when atoms have 8 electrons in their valence shell (except for hydrogen and helium, which are stable with 2 electrons).

Types of Chemical Bonds

• There are three types of chemical bonds: ionic, covalent, and metallic.

Ionic Bonds

• Formed between a metal atom and a non-metal atom.
• Characterized by a large difference in electronegativities (>1.7) between the atoms.
• One atom loses an electron, which is attracted by the more electronegative atom.
• Example: sodium chloride (NaCl), where sodium loses an electron to chlorine.

Covalent Bonds

• Formed between two non-metal atoms.
• Characterized by sharing electrons between atoms.
• Three types of covalent bonds: non-polar, polar, and coordinate.

Non-Polar Covalent Bonds

• Formed between two identical atoms.
• Example: hydrogen molecule (H2), where two hydrogen atoms share electrons to become stable.

Polar Covalent Bonds

• Formed between two different non-metal atoms.
• Characterized by a difference in electronegativities (>0 but <1.7) between the atoms.
• Example: water molecule (H2O), where oxygen attracts electrons from hydrogen to complete its octet.

Metallic Bonds

• Formed between metal atoms.
• Characterized by a "sea of electrons" that allows metals to conduct electricity, heat, and have a characteristic luster.