What to Memorize: Exam 1

Chemistry

Chemistry

the study of the properties and behavior of matter.

Matter

the physical material of the universe; anything that has mass and takes up space.

Property

any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types.

Elements

substances that combine together to create matter.

Atoms

the tiniest particles that are the building blocks of matter and cannot be divided further.

Molecules

two or more atoms bonded together.

Protons

positively charged particles found in the nucleus of an atom.

Neutrons

neutral particles found in the nucleus of an atom.

Electrons

negatively charged particles that orbit the nucleus of an atom.

Atomic number

the number of protons in an atom.

Mass number

the total number of protons and neutrons in an atom.

Average mass

the weighted average of the masses of all isotopes of an element.

Alkali metals

Group 1A elements in the periodic table.

Alkaline earth metals

Group 2A elements in the periodic table.

Transition metals

Groups 3-12 elements in the periodic table.

Halogens

Group 7A elements in the periodic table.

Noble gases

Group 8A elements in the periodic table.

Polyatomic ions

ions composed of two or more atoms.

Percent composition

the percentage by mass of each element in a compound.

Avogadro’s number

6.022 × 10²³, the number of particles in one mole of a substance.

Percent yield

the ratio of actual yield to theoretical yield expressed as a percentage.

Chemical reaction symbols

notation used to represent the states of matter in a chemical reaction (g, l, s, aq).

Organic molecules

molecules primarily made of carbon, such as methane, ethane, and propane.

Density formula

Density = mass/volume (D = m/V).

Metric prefixes

symbols that denote powers of ten (e.g., Giga = 10⁹, Mega = 10⁶).