chem wk3 tuesday

Ionic Compound

A compound formed from a metal and a nonmetal, where electrons are transferred from one atom to another to produce positive and negative ions.

Molecular Compound

A compound (also known as a covalent compound) formed from nonmetals that share electrons between atoms.

Molecular Formula

A chemical formula that specifies the actual number of each type of atom present in a single molecule of a compound.

Structural Formula

A formula that illustrates how atoms in a molecule are connected and arranged spatially.

Diatomic Elements

Seven elements that naturally exist as two-atom molecules when uncombined: $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, and $I_2$.

Molecule vs. Compound

A molecule is any group of two or more chemically bonded atoms (same or different elements), whereas a compound must contain two or more different elements chemically combined.

Empirical Formula

The simplest whole-number ratio of atoms or ions present in a substance.

Formula Unit

The simplest lowest whole-number ratio of ions represented in an ionic compound's repeating crystal lattice.

Isomers

Compounds that share the exact same molecular formula but have different structural arrangements and distinct properties.

Dmitri Mendeleev

The chemist who organized an early periodic table by atomic mass and successfully predicted the existence of undiscovered elements by leaving blank gaps.

Henry Moseley

The scientist who established atomic number as the organizing basis for the modern periodic table.

Modern Periodic Law

The principle stating that the physical and chemical properties of elements are periodic functions of their atomic numbers.

Period vs. Group

A period is a horizontal row on the periodic table; a group (or family) is a vertical column containing elements with similar chemical properties due to valence electron patterns.

Properties of Metals

Elements that are typically shiny, malleable (shapeable), ductile (draw-able into wires), and efficient conductors of heat and electricity.

Alkali Metals

Group 1 elements (excluding hydrogen) that are highly reactive non-gases and typically form $+1$ main-group cations.

Alkaline Earth Metals

Group 2 elements that typically form $+2$ cations.

Halogens

Group 17 highly reactive nonmetals ('salt-formers') that typically form $-1$ main-group anions.

Noble Gases

Group 18 unreactive gases that possess stable electron configurations and form ions with a charge of $0$.

Valence Electrons

Electrons located in the outermost occupied energy level of an atom that are directly involved in chemical bonding and reactions.

Cation

A positively charged ion formed when an atom or group of atoms loses electrons.

Anion

A negatively charged ion formed when an atom or group of atoms gains electrons.

Polyatomic Ion

A charged group of two or more covalently bonded atoms that functions collectively as a single ion.

Oxyanion Naming Rules

The suffix '-ate' contains more oxygen atoms than '-ite'; prefix 'per-' designates the highest oxygen count in a series, while 'hypo-' designates the lowest.

Chemical Bond

A durable electrostatic attraction between atoms or ions that binds them together.

Properties of Ionic Compounds

Typically high-melting, high-boiling crystalline solids at room temperature that conduct electricity when molten or dissolved in liquid.

Properties of Molecular Compounds

Compounds with lower melting and boiling points relative to ionic compounds, often existing as gases or liquids and failing to conduct electricity well.

Molecular Prefixes (1-10)

mono- ($1$), di- ($2$), tri- ($3$), tetra- ($4$), penta- ($5$), hexa- ($6$), hepta- ($7$), octa- ($8$), nona- ($9$), deca- ($10$).