Chemistry A: Elements, Compounds, and Mixtures

Element

A pure substance consisting of only one type of atom; cannot be broken down into simpler substances by chemical means.

Metal

A class of elements that are good conductors of heat and electricity, malleable, ductile, and have high melting or boiling points.

Non-metal

Elements that are poor conductors of heat and electricity, typically brittle, and possess lower melting and boiling points.

Metalloid

Elements that have properties intermediate between metals and nonmetals.

Noble Gases

Inert, unreactive gases with full valence electron shells.

Halogens

Highly reactive nonmetals that form salts with metals.

Chemical Compound

A substance formed when two or more elements are chemically bonded together in fixed proportions.

Ionic Compound

A compound made of a metal and a non-metal that has high melting points and conducts electricity in molten or aqueous states.

Covalent Compound

A compound formed between non-metals that exist as molecules and generally have low melting and boiling points.

Metallic Compound

A compound formed from metal atoms that are malleable, ductile, and conduct electricity and heat.

Ionic Bonding

A chemical bond resulting from the transfer of electrons from metals to non-metals.

Covalent Bonding

A type of bonding that involves the sharing of electron pairs between atoms.

Metallic Bonding

A type of bonding found in metals, characterized by a sea of delocalized electrons around metal cations.

Homogeneous Mixture

A mixture that has a uniform composition throughout.

Heterogeneous Mixture

A mixture that does not have a uniform composition and properties throughout.

Filtration

A separation technique that separates solids from liquids.

Distillation

A separation technique that separates liquids based on their different boiling points.

Chromatography

A separation technique that separates components based on their solubility and adsorption properties.

Empirical Formula

The simplest whole-number ratio of atoms in a compound.

Molecular Formula

The actual number of atoms of each element in a molecule.

Transition Metals

Elements found in the d-block of the periodic table that exhibit variable oxidation states and form colored compounds.