FallFinalReview2425

proton

A positively charged particle in the nucleus of an atom.

electron

A negatively charged particle that orbits the nucleus of an atom.

neutron

A neutrally charged particle in the nucleus of an atom.

atom

The smallest unit of a chemical element, composed of protons, neutrons, and electrons.

mass number

The total number of protons and neutrons in an atomic nucleus.

average atomic mass

The weighted average mass of the isotopes of an element.

atomic number

The number of protons in the nucleus of an atom, determining the element's identity.

atomic mass unit (amu)

A unit of mass used to express atomic and molecular weights.

isotope

Different forms of an element that have the same number of protons but different numbers of neutrons.

ion

An atom or molecule that has gained or lost one or more electrons, resulting in a net charge.

octet rule

The principle that atoms tend to bond in such a way that they each have eight electrons in their valence shells.

element

A pure substance consisting of one type of atom.

compound

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

chemical reaction

A process that leads to the transformation of one set of chemical substances to another.

radioactive decay

The process by which an unstable atomic nucleus loses energy by radiation.

significant figures

The digits in a number that carry meaningful information about its precision.

dimensional analysis

A mathematical technique used to convert units from one system to another.

conversion factor

A ratio used to convert from one unit to another.

valence electron

An electron in the outermost shell of an atom that can participate in chemical bonding.

Bohr model

A model of the atom that depicts electrons in fixed orbits around the nucleus.

density

The mass of a substance per unit volume.

periodic table

A tabular arrangement of the elements, organized by increasing atomic number.

group

A vertical column in the periodic table.

period

A horizontal row in the periodic table.

unit of measurement

A definite amount of a quantity used to quantify a physical property.

base unit

A fundamental unit of measurement in the metric system.

metric scale

A system of measurement based on powers of ten.

prefix

A scaling factor added to a unit of measurement to indicate multiples or fractions.

scientific notation

A way of expressing numbers as a multiple of a coefficient and a power of ten.

pure substance

Matter that has a constant composition and distinct chemical properties.

mixture

A combination of two or more substances that retain their individual properties.

homogeneous mixture

A mixture that has a uniform composition throughout.

heterogeneous mixture

A mixture in which the composition is not uniform throughout.

extensive properties

Properties that depend on the amount of matter present.

intensive properties

Properties that do not depend on the amount of matter present.

plum pudding model

An early model of the atom proposed by J.J. Thomson, depicting electrons embedded in a positive charge.

nuclear decay

The process by which an unstable atomic nucleus loses energy and mass.

photon

A quantum of electromagnetic radiation.

wavelength

The distance between successive crests of a wave.

frequency

The number of waves that pass a given point in a certain amount of time.

Planck's constant

A fundamental constant used to describe the sizes of quanta in quantum mechanics.

speed of light

The speed at which light travels in a vacuum, approximately 3.00 x 10^8 m/s.

alkali metals

Group 1 elements in the periodic table that are highly reactive.

noble gases

Group 18 elements known for their lack of reactivity due to having a full valence shell.