College Chem

Matter

The physical material of the universe; it is anything that has mass and occupies space.

Gas

No fixed volume or shape. Uniformly fits its container. Can be compressed.

Liquid

Distinct volume assuming the shape of the portion of the container it occupies. Non-compressible.

Solid

Defined volume and shape. Non-compressible.

Physical change

Changes in appearance not composition. (Water changing states/melting/freezing/evaporating)

Chemical change

Transformation to a chemically different substance (reaction/bonding/breaking bonds)

Pure Substance

Consists of 1 type of atom or chemically bonded atom. Defined and constant composition.

Element

Pure substance with only 1 type of atom (on periodic table)

Compound

Pure substance with multiple bonded atoms/elements

Mixture

2 or more substances physically combined not bonded.

Hetero mixture

Can see that it’s not bonded/not uniform. Ex: salsa, cereal, gravel

Homo mixture

Uniform/ can’t see that it’s not bonded). Ex: Kool-aid, brass, steel

Significant Figure

Not a zero, a zero between non-zeros, at the end of a decimal, in the coefficient of a number written in scientific notation.

Mass

Amount of matter (g,kg,lb)

Volume

The amount of space. (L,mL,gallons,etc)

When multiplying to get an answer with significant digits report the answer with…

The fewest s/d

When adding or subtracting significant digits report the answer with…

The fewest place value/decimal points

Proton

Positive charged particle found in the nucleus of an atom. 1 weight

Neutron

Neutrally charged particle with largest mass in an atom also found in the nucleus.

Electron

Negatively charged particles with NO mass found in the orbitals of an atom.

Atomic Number

Number of protons

Mass number

Number of protons + number of neutrons

Isatopes

Atoms with identical atomic numbers but different mass numbers. (Different number of neutrons but same number of protons)

Democritus

First man to theorize that the world is made up of “tiny invisible units”. (Atoms) No evidence for his theories.

John Dalton

1808 theorist who said atoms can’t be broken to smaller pieces and created the Law of Definite Proportions: A chemical compound always contains the same proportion of a particular element.

JJ Thomson

1897 theorist who discovered Cathode Rays by using a vacuum tube to isolate 2 particles, one negatively charged and one positive, and shot them to create the ray which could be deflected with a magnet. Discovered the Electron

Ernest Rutherford

Student of JJ Thomson who tested to find out that an atoms mass is spread evenly throughout a volume. Aimed a Cathode Ray through a sheet of gold and found that some went through but some didn’t concluding that atoms are denser in the middle/ nucleus.

Period

A horizontal row in the periodic table

Group

The vertical line of elements on the periodic table. Has the same number of valence electrons

Metal properties

Shiny, malleable (can be hammered into sheets), conducter, ductile (can be drawn into wires).

Nonmetal properties

Dull, brittle solids that are poor conductors

Metalloid Properties

Shiny, brittle solids that are semi-conductors. Can have some metal+nonmetal properties.

Ion

An atom with a charge due to a difference in protons and electrons

Cation

A POSITIVE ion with more protons then electrons

Anion

A NEGATIVE ion with more electrons then protons

Polyatomic ions

A group of elements with a charge (golden ticket)

Ionic compounds

Metals+Nonmetals (poly), on golden ticket, Roman numerals, cross cross, NO prefixes

Molecular compounds

Nonmetal+Nonmetal, use prefixes

Noble gases

Transition Metals

Halogens

Alkali Metals

Lanthanides

Actinides

Nonmetals

Basic Metals

Metalloid

Acids

Compound that starts with H

Molecular formula

The actual number of atoms in a molecule

Empirical formula

The simplest reduced form of a molecule