Atoms, Isotopes, and the Periodic Table

Vocabulary flashcards covering atoms, subatomic particles, periodic table regions, chemical formulas, ions, isotopes, mass numbers, and isotopic abundance calculations.

Elements

The fundamental material of all substances of matter that allows chemists to predict chemical reactions, formulas of compounds, relative sizes and shapes of atoms and molecules, and solubility in water or oil.

Metals

A region of elements on the periodic table that are good conductors of electricity and heat, solid at room temperature (except mercury, which is liquid), have high melting points, and form metallic bonds.

Non-metals

Elements on the periodic table that do not conduct electricity or heat, can exist as solids, liquids, or gases, and have melting points lower than metals.

Metalloids

Elements with properties intermediate between metals and non-metals, showing a gradual change of physical properties across elements.

Chemical Formula

A shorthand method for showing the elements present in a compound by their atomic symbols and the number of each element using subscripts.

Proton

A subatomic particle found in the nucleus of an atom with a mass of $1\,\text{amu}$ and a charge of $+1$.

Neutron

A subatomic particle found in the nucleus of an atom with a mass of $1\,\text{amu}$ and a neutral ($0$) charge.

Electron

A subatomic particle orbiting the nucleus of an atom with a mass of $0\,\text{amu}$ and a charge of $-1$.

Atomic Number ($Z$)

The number located at the top of an element's square on the periodic table, which equals the number of protons in an atom.

Atomic Symbol ($X$)

A 1 or 2 letter abbreviation used to represent an element's name.

Atomic Mass

The mass of an atom listed at the bottom of an element's square on the periodic table (usually a decimal), measured in atomic mass units ($\text{amu}$).

Ion

A form of an atom in which electrons have been gained or lost, resulting in an overall charge equal to the net number of electrons gained or lost.

Isotope

Atoms of the same element that have different numbers of neutrons, differing only in mass while retaining identical chemical properties.

Mass Number ($A$)

The total mass number of a specific isotope, calculated as $\text{Mass Number} = \text{\# of Protons} + \text{\# of Neutrons}$.

Protium

The isotope Hydrogen-1, consisting of $0$ neutrons, $1$ proton, $1$ electron, and a mass number of $1$.

Deuterium

The isotope Hydrogen-2, consisting of $1$ neutron, $1$ proton, $1$ electron, and a mass number of $2$.

Tritium

The isotope Hydrogen-3, consisting of $2$ neutrons, $1$ proton, $1$ electron, and a mass number of $3$.

Atomic Mass Equation

The formula used to calculate atomic mass: $\text{Atomic mass} = (\text{mass of isotope 1})(\%\text{ abundance}) + (\text{mass of isotope 2})(\%\text{ abundance}) + \dots$

Isotope Symbol Notation

A symbol format where $A$ represents the atomic mass number (protons + neutrons), $Z$ represents the atomic number (protons), and $X$ represents the element symbol.

Periodic Table Entry (Gold)

A standard periodic table square showing atomic number $Z = 79$ at the top, element symbol $\text{Au}$, element name Gold, and atomic mass $196.9665\,\text{amu}$ at the bottom.