Ionic bonding is the giving away and taking of electrons, typically occurring in water or aqueous solutions, and commonly involving salts.
Valence electrons and valence shell: the outermost electron shell of an atom; tendency is to have a filled valence shell (octet rule) whether electrons are given away, taken, or shared.
Octet rule concept mentioned: aim for eight electrons in the valence shell; for H, the first shell is filled with two electrons.
Example walkthrough (carbon and oxygen):
Carbon (C): atomic number 6; nucleus with 6 protons.
First shell holds 2 electrons; second shell holds 8 maximum but carbon currently has 4 electrons in the second shell, hence needs 4 more.
Oxygen (O): proton count 8; first shell has 2 electrons; second shell has 6 electrons; needs 2 more to complete octet.
Oxygen and carbon interact by sharing electrons; this can lead to various bonding patterns depending on electron sharing or transfer, resulting in an octet for each participating atom.
Nonpolar covalent bonding vs polar covalent bonding (major distinction):
Nonpolar covalent bonds: equal sharing of electrons; examples include bonds where atoms have similar electronegativities (e.g., O=O, N≡N); geometry can be linear for some molecules (e.g., CO₂, O₂).
Polar covalent bonds: unequal sharing of electrons due to differences in electronegativity; creates partial charges (δ− on the more electronegative atom and δ+ on the less electronegative atom).
Water and polarity:
Water (H₂O) is a classic polar molecule due to unequal sharing where oxygen pulls electron density more strongly from hydrogen.
This unequal sharing creates a dipole moment; partial charges develop (δ− on O, δ+ on H).
Oxygen’s stronger pull results in electrons spending more time near O, giving O a partial negative charge