Chemical bonds are the glue that holds atoms together in molecules and compounds. Understanding the different types of chemical bonds and their properties is fundamental to learning about chemistry. Today we’ll talk about ionic, covalent, and metallic bonds.

✨ Ionic, Covalent, and Metallic Bonds

Ionic Bonds

Ionic bonds are formed through the transfer of electrons from a metal to a non-metal. For example, NaCl 🧂 is an ionic bond! This electron donation and acceptance result in positively charged ions (cations) and negatively charged ions (anions). The bond forms due to the electrostatic attraction between these oppositely charged ions.

Key Features:

• Formed between metals (which lose electrons) and non-metals (which gain electrons).
• Results in ionic compounds with distinct positive and negative ions.
• Usually creates crystalline solids with high melting and boiling points.
• Soluble in polar solvents (ex. water).
• Conduct electricity when dissolved and/or molten. This happens because the ions will separate!

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Practice Question

Which of these compounds would most likely form an ionic bond? A) CO₂ B) SO₂ C) MgCl₂ D) H₂

Answer: c

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Covalent Bonds

Covalent bonds occur when two non-metal atoms share one or more pairs of electrons. The shared electrons will hold the atom together.

Key Features:

• Can be either polar covalent (unequal sharing of electrons) or nonpolar covalent (equal sharing of electrons).
• Due to unequal electron density distribution, polar covalent molecules have partial charges on each end.
• Nonpolar covalent molecules have no charge separation as electrons are equally shared.
• Has lower melting and boiling points when compared to ionic bonds.

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Practice Question

Which of the following best describes a covalent bond?

a) The transfer of electrons between atoms.

b) The sharing of electrons between atoms.

c) The attraction between oppositely charged ions.

d) The interaction of metal atoms with metallic properties.

Answer: b

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Metallic Bonds

Metallic bonds are unique; they are found within pure metals or alloys where free-electron clouds move around positively charged atomic nuclei arranged in lattice structures.

Key Features:

• Electrons can flow freely through metals. This allows the metal to conduct electricity easily.
• Responsible for other metallic properties like malleability (the ability to be hammered into thin sheets) and ductility (the ability to be drawn into wires).

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Practice Question

What property is most characteristic of metals due to metallic bonding?

A) Low melting point B) Poor conductivity C) High malleability D) Insolubility in water

Answer: c

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📈 Electronegativity & Bond Type

Electronegativity differences between atoms play a crucial role in determining bond type:

1. When one atom has a significantly higher electronegativity than another, it's likely an ionic bond will form as one atom strips an electron away from another—as sodium does with chlorine.
2. If both atoms have similar electronegativity values, they're more inclined towards sharing their outer-most electrons equally—resulting in a nonpolar covalent bond—like what occurs between carbon atoms or diatomic elements such as O₂ or N₂.
3. Lastly, if there's some difference—but not enough for complete transfer—an uneven sharing occurs leading to polar covalent bonding—as seen with H₂O's oxygen pulling more on hydrogen's shared electrons creating slight charges at each end.

Remember! To determine the type of bond that will most likely form, find the electronegativity difference:

Now that you've familiarized yourself with these principles put your knowledge into practice! Work through more practice questions in our practice sets. Happy Studying! ⚗️