Chemical Bonding Review

Flashcards reviewing chemical bonding concepts.

Why do atoms bond?

Atoms bond to achieve a more stable electron configuration.

Chemical Bond

Simultaneous attraction for the same electrons by two different nuclei.

Bond formation

Exothermic; stability increases.

Bond breaking

Endothermic.

BARF

Breaking (bonds) Absorbs (energy) Releases (energy) Forming (bonds).

Ionic bond

Formed when a metal transfers one or more electrons to a nonmetal.

Covalent bond

Formed when two non-metallic atoms share electrons.

Nonpolar covalent bonds

Exist between atoms of the same element.

Polar covalent bonds

Exist between two different nonmetallic atoms.

Metallic bonds

Exist in solid metals; consist of 'fixed' nuclei and mobile electrons.

Ionic compounds

Contain ionic bonds between positive and negative ions (metal ions, nonmetal ions, and/or polyatomic ions).

Polyatomic ions

Groups of covalently bonded atoms with an overall charge; compounds containing these have both ionic and covalent bonds.

Properties of ionic compounds

Exist as hard solids with a crystal lattice structure; have high melting and boiling points; conduct electricity when melted or dissolved in water.

Covalent/Molecular compounds

Contain only nonmetals and exist as molecules; have low melting and boiling points; do not conduct electricity in any state of matter.

Lewis structures for ionic compounds

Write the symbol for the metal, draw no dots, brackets and the charge. Write the symbol for the nonmetal, draw 8 valence dots inside the brackets and give the charge.

Lewis structures for covalent compounds

Two electrons are shared to form 1 bond and all atoms must have a share of eight valence electrons.

Intermolecular Forces of Attraction (IFAs)

Hold molecules together in the liquid and solid phases and are responsible for physical properties such as boiling point, melting point, vapor pressure and solubility.

Relationship between IFA strength and boiling/melting point

The stronger this force, the higher the boiling and melting points.

Nonpolar molecule IFAs

The weakerst IFA and are present in nonpolar molecules.

Polar molecule IFAs

Stronger than nonpolar IFAs and are present in polar molecules.

Hydrogen bonds

Unusually strong IFAs that occur when an H atom is bonded to F, O, or N.

Molecule-ion attraction

The positive ion from the salt is attracted to the negative oxygen, and the negative ion is attracted to the positive hydrogen.

Polarity of molecules/ionic character

Determined by electronegativity differences; greater difference means more polar/more ionic character.

CO2

Nonpolar, symmetrical.

HF

Polar, asymmetrical.

SNAP

Symmetrical - nonpolar; Asymmetrical - polar.

Like dissolves like (polar)

Polar molecules and ionic compounds dissolve in polar solvents.

Like dissolves like (nonpolar)

Nonpolar molecules dissolve only in nonpolar solvents.