Ionic, Covalent, and Metallic Bonds

Chemical Bonds

★ two atoms or more that are joined together via nuclei and valence electrons

Why do atoms bond to form compounds?

"Atoms are like single girls at a club or a bar. They're high energy! I had friends like that when I was in college. They were always crazy, so I'm always like, 'What on earth are you doing?' But when they get into relationships, their energy is lowered. Instead of going out and being crazy, they're at home watching movies." ~Mrs. Moos

★ high potential energy → form bonds → lower potential energy → more stable

    ☆ noble gases are already stable

Octet Rule

★ Atoms have a goal to achieve stability

★ Stable with 8 valence electrons



★ Boron's stable with 6 valence electrons

★ Some elements have bigger valence shells are in the d and p blocks.

Types of Bonds

Ionic Bond

★ metal + nonmetal

★ greater electronegativity difference

★ formed by electron transfer from metal to nonmetal

    ☆ one atom gains electrons while the other loses electrons

    ☆ cation + anion

★ Examples: NaCl

Covalent Bond

☆polar →uneven sharing of electrons ★ non-polar →even sharing of electrons

★ nonmetal + nonmetal

★ electrons are shared

    ☆ sharing is not always equal (I should know, I have a younger sister)

        ☂ polar covalent → uneven sharing

        ☂ non-polar covalent → even sharing

★ Example: CO2

Polar Covalent Bond

★ atoms have significant difference in electronegativity values

★ electrons more attracted to atom with higher electronegativity

    ☆ electrons hang out with higher electronegativity (stronger atom)

    ☆ electrons/charge distributed unevenly

★Example: H2O

Nonpolar Covalent Bond

★ atoms have no or not a significant difference in electronegativity values

★ electrons/charge distributed evenly

★ Example: CH4

Metallic Bond

★ metal + metal

★ electrons shared equally

★ delocalized electrons

    ☆ electrons have freedom to move

   ☆ "sea of electrons"

★ Example: Hg

★ semi-vacant p & d orbitals → delocalized electrons → electrons easier to move through metal → conductivity

Characteristics of Ionic, Covalent, and Metallic Bonds

☂ Ionic bonds don't conduct when solid

☂ Covalent bonds never conduct

☂ Metallic bonds always conduct and don't dissolve

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