3 Chemical Bonding and Lewis Structures Free Online FlashCards

What do lines and dots represent in a Lewis structure?

A Lewis structure represents valence electrons: lines show shared electron pairs in bonds, and dots show lone pairs.

How does an ion’s charge change its Lewis-structure electron count?

Adjust the total valence-electron count by adding one electron per negative charge and subtracting one per positive charge.

How is the central atom usually chosen for a Lewis structure?

Choose the least electronegative atom, except hydrogen, as the central atom in the usual skeleton. Connect the atoms first with single bonds.

Does every atom in a Lewis structure follow the octet rule?

The octet rule is a useful guide, especially for second-row elements such as C, N, O, and F, but it is not universal. Hydrogen follows a duet rule.

What checks and preferences help evaluate formal charges?

Formal charges must sum to the species’ overall charge. When comparing valid structures, prefer minimizing formal charges and avoid placing negative formal charge on a less electronegative atom when reasonable.

What does resonance mean in a Lewis-structure description?

Resonance structures have the same atom arrangement but differ in electron placement. The actual species is a delocalized resonance hybrid, not a structure rapidly switching between drawings.

How does bond order generally affect bond length and strength?

For the same pair of atoms, greater bond order generally means a shorter and stronger bond. A triple bond is generally shorter and stronger than a double bond, which is shorter and stronger than a single bond.

How do bond energy and lattice energy differ?

Bond energy is the energy required to break a specified bond in gaseous molecules; reported values for a bond type are averages. Ionic solids are described using lattice energy, reflecting collective ion attractions.

What holds oppositely charged ions together in ionic bonding?

Ionic bonding is the electrostatic attraction between positively and negatively charged ions.

How are ions arranged in an ionic solid such as NaCl?

Ionic attractions extend in all directions, forming a crystal lattice rather than separate NaCl molecules.

What does the formula NaCl indicate about an ionic solid?

NaCl represents the simplest whole-number ratio of sodium ions to chloride ions in the solid.

What defines a covalent bond?

A covalent bond forms when atoms share one or more pairs of electrons.