2Q_Science_A

Atom

contain a positively charged nucleus composed of neutrons and protons.

Bohr’s Atomic model

electrons revolve around the nucleus in orbits that increase in energy the farther they get from the nucleus.

Quantum Mechanical Model

electrons occupy whose location and energy are described by four quantum numbers

Valence Electrons

are the electrons in the outermost energy level.

Valence Electrons

they play a key role in chemical bonding.

Ion

forms when an atom gains or loses electrons.

Ion

it can be positively charged (cation) or negatively charged (anion)

Ionic Bond  

forms when a metal transfers electrons to a nonmetal.

Covalent Bond

forms when two non metals share electrons

Metallic Bond

result from the attraction between the positive metal kernel and the delocalized electrons.

Lewis Dot Structure

Diagram that shows valence electrons and bonding in atoms/molecules.

Valence Electrons

Electrons in the outermost shell involved in bonding.

Electron Pair

Two electrons grouped together (bonding or nonbonding).

Bonding Pair

A pair of electrons shared between atoms to form a bond.

Lone Pair

A pair of electrons on one atom that is not shared

Covalent Bond

A bond formed when atoms share electron pairs

Single Bond

One shared pair of electrons (—).

Double Bond

Two shared electron pairs (=).

Triple Bond

Three shared electron pairs (≡).

Octet Rule

Atoms try to have 8 valence electrons for stability

Expanded Octet

Atoms in Period 3+ can have more than 8 valence electrons.

Formal Charge

Tool to check structure stability using electron counting.

Resonance

When a molecule can be drawn with more than one valid structure

Electron Dot Symbol

Element symbol with dots showing its valence electrons.

Ionic Bond

A bond formed when one atom transfers electrons to another, creating oppositely charged ions.

Ionic Compound

A compound made of cations and anions held together by ionic bonds

Ion

An atom or group of atoms with a positive or negative charge.

Cation

A positively charged ion formed by losing electrons.

Anion

A negatively charged ion formed by gaining electrons.

Electron Transfe

The movement of electrons from one atom to another during ionic bonding.

Electrostatic Attraction

The force that pulls opposite charges together in an ionic bond.

Crystal Lattice

A repeating, orderly arrangement of ions in an ionic solid.

Formula Unit

The simplest whole-number ratio of ions in an ionic compound

Polyatomic Ion

A charged group of atoms bonded together acting as a single ion

Valence Electrons

Electrons in the outermost shell involved in forming ions

Oxidation State

A number indicating how many electrons an atom gained or lost

Conductivity

Ability to conduct electricity when melted or dissolved due to mobile ions

High Melting Point

A property caused by strong ionic attractions in the lattice

Solubility

The ability of ionic compounds to dissolve in water