Module 2: Atoms, molecules, and Ions

Law of conservation of mass

mass is neither created nor destroyed in a chemical reaction

Law of definite proportions

A given compound always contains exactly the same proportion of elements by mass

Law of multiple proportions

When two elements form a series of compounds the ratio of masses of the second element—

Electronegativity

the ability of an atom in a covalent bond to attract shared electrons to itself

What has the highest electronegativity

Fluorine

Oxidation number

Imaginary charges on atoms in compounds that allow us to keep track of electrons and oxidation-reduction reactions

Oxidation

Loss of electrons/ increase in oxidation number

Reduction

Gain of electrons/ decrease an oxidation number

Arrhenius Acid

Increases the H+ concentration/ gives H+ in water

Arrhenius base

increases OH- in aqueous solutions (accepts H+)

Salt

Another name for an ionic compound. Formed when an acid reacts with a base or when a metal reacts with a non-metal

Neutilization

Acid + Base + Neutralization

The eight active metals

Li, Na, K, Rb, Cs, Ca, Sr, Ba

Description of an acid-base reaction

A reaction in which H+ ions are transferred

Acid base reaction equation

Acid + Base = Salt +water

Description of Oxidation reduction reaction

A reaction in which electrons are transferred or when the oxidation number changes

Equation oxidation reduction reaction

Active metal + water= H2 + metal hydroxide

Precipitation reaction

A reaction in which one of the products out of the solution as a solid

Equation Precipitation reaction

1 (aq) + 2 (aq) = 3 (s) + 4 (aq)