Atomic Structure, Isotopes, and Periodic Table Vocabulary

A collection of vocabulary flashcards covering basic atomic structure, subatomic particles, periodic table trends, electron diagrams, ions, and isotope notation.

Proton

A subatomic particle located in the nucleus with a positive ($+1$) charge and a mass of $1\,amu$.

Neutron

A subatomic particle located in the nucleus with a neutral ($0$) charge and a mass of $1\,amu$.

Electron

A subatomic particle located in the electron cloud with a negative ($-1$) charge and a mass of approximately $\frac{1}{2000}\,amu$.

Atomic Number

The number of protons in the nucleus of an atom, represented by $Z$, which uniquely identifies the element.

Mass Number

The total number of protons and neutrons ($p^+ + n^0$) in an atom's nucleus, represented by $A$.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Radioactive Isotopes

Isotopes with unstable nuclei that break down over time; they are dangerous to living things but useful as scientific tools.

Average Atomic Mass

The calculated weighted average mass of all naturally occurring isotopes of an element.

Groups (Periodic Table)

The vertical columns of the periodic table; all elements in a column have the same number of valence electrons.

Periods (Periodic Table)

The horizontal rows of the periodic table, where the row number indicates how many electron shells an atom has.

Metals

Elements that are good conductors of heat and electricity, shiny, stretchable, and bendable.

Non-metals

Elements that are poor conductors, good insulators, dull in appearance, and brittle.

Metalloids

Elements with intermediate properties between metals and non-metals that function as semiconductors.

Bohr Model

A diagram that shows the total number of protons, neutrons, and electrons in an atom, as well as the specific electron shells where electrons are found.

Valence Shell

The outermost electron shell of an atom.

Valence Electrons

The electrons located in the outermost electron shell (valence shell) of an atom that participate in chemical bonding.

Lewis Structure

A diagram (also known as a Lewis dot structure) showing an element's chemical symbol surrounded by dots representing only its valence electrons.

Ion

A charged atom formed due to the gain or loss of electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Isotope Notation

A standardized format showing an element's symbol ($\text{X}$), mass number ($A$), atomic number ($Z$), and charge ($C$).