Gen Chem 1010 Module 2

Atoms, Molecules, Ions

Law of Conservation of Mass/Matter

mass is neither created or destroyed in the course of 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 2 elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the 1st element can always be reduced to whole numbers

atom

smallest part of an element which retains the chemical properties of the element

Molecule

A neutral structure consisting of two or more atoms that are chemically bound together and behave as an independent unit

1st postulate of atomic theory of matter

each element is made up of tiny particles called atoms

2nd postulate of atomic theory of matter

the atoms of a given element are identical; the atoms of different elements are different in some fundamental way

3rd postulate of atomic theory of matter

chemical compounds are formed when atoms of different elements combine with each other. A given compound always has the same relative numbers and types of atoms

4th postulate of atomic theory

Chemical reactions involve reorganizations of the atoms changes the way they are bound together. The atoms themselves are not changed in a chemical reaction

1/1800

approximate mass of electron in amu

1

approx. mass of proton amu

1

approx. mass of neutron in amu

10^-18

approximate diameter of atom

Ion

an atom that has a charge

Nucleus

positively charged center of an atom made up of protons and neutrons

Atomic number

number of protons in the nucleus of an atom

mass number

thee sum of the numbers of neutrons and protons in the nucleus of an atom

Isotopes

Atoms that contains the same number of protons but different numbers of neutrons

properties of metals

conducts heat and electricity, malleable (beaten into sheets), ductile (drawn into wires), solid at room temp (hg is liquid), lustrous (shiny), cations

properties of nonmetals

Don’t conduct heat or electricity, not malleable or ductile, most are gas or solid (Br2 is liquid), solid and brittle, anions

Alkali Metals

1A

Alkaline Earth Metals

2A

Halogens

7A

Noble Gases

8A

Lathanides

top row of bottom two rows of the table

Actinides

bottom row of the bottom two rows of the table

transition metals

“B” metals

Electronegativity

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

Oxidation

electron loss or increase in oxidation number

Reduction

electron gain or decrease in oxidation number

Arrhenius acid

A substance which produces H+ in a solution

Arrhenius base

A substance which produces OH- in solution

Salt

an ionic compound (cation + anion)

Neutralization

a chemical reaction between an acid and base, the point that both are exactly used up, resulting in the formation of salt and water

Precipitation reaction

two soluble substances combine to form an insoluble solid that separates from the solution

Combustioni

Vigorous reaction with oxygen to produce heat and/or light (burning)

Decomposition reaction

A reaction in which a single reactant breaks down to two or more simpler compounds or elements

8 active metals (which combine with hydroxides to act as bases)

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

acid + base —> salt + water

Acid-base general equation

Acid-base reaction

a reationi in which H+ ions are transferred

Oxidation-reduction

a reaction in which electrons are transferred or in which oxidation numbers change

Active metal + water —> metal hydroxide + hydrogen gas (h2)

type of oxidation-reduction reaction

CH(O) compound + oxygen —> Carbon Dioxide + Water

Combustion reaction (oxidation reduction)