Periodic Families, Trends, and Nuclear Reactions

Vocabulary practice flashcards covering periodic families, stellar nucleosynthesis, nuclear decay modes, fission reactions, and periodic trends.

Period

A horizontal row across the periodic table characterized by an increasing number of protons when moving to the right. There are $7$ periods in total.

Group

A vertical column on the periodic table containing elements that all share the same number of valence electrons. There are $18$ groups in total.

Alkali Metals

Group $1$ elements that are highly reactive and explosive metals due to having only $1$ valence electron.

Alkaline Earth Metals

Group $2$ elements that are the second most reactive metals because they possess $2$ valence electrons.

Transition Metals

Metals in groups $3$–$12$ that are unique for forming multiple different cations (such as $2+$, $3+$, or $4+$) and are widely used to make tools, structures, wiring, and jewelry.

Post-Transition Metals

Metals located to the right of the transition metals that are softer and have lower melting points, commonly carrying charges of $+3$ (or $+2$ and $+4$), used in malleable products and high-tech items like aluminum foil and gallium electronics.

Metalloids

Unique elements that can act as both metals and nonmetals, possessing the ability to form both anions and cations.

Reactive Non-Metals

Elements that form negative charges and have very low melting points, with the exception of carbon.

Halogens

The most reactive group of nonmetals, possessing $7$ valence electrons and commonly reacting with alkali and alkaline earth metals.

Noble Gases

Elements that do not react much, if at all, because they possess a stable, perfect octet of valence electrons.

Lanthanides

A series of shiny white metallic elements located below the main body of the periodic table that display varying chemical and physical properties.

Actinides

A series of extremely radioactive, unstable, and very short-lived metallic elements.

Nuclear Fusion

The process in stars where hydrogen atoms collide under extreme temperature and pressure to form helium and other heavier elements up to iron.

Supernova

An explosion marking the death of a star that produces enough energy for hydrogen and helium to collide into elements heavier than iron and scatter them into space.

Nuclear Decay

The process where an unstable atom breaks apart into smaller, more stable atoms because too many protons packed closely together repel one another.

Alpha Decay

A form of radioactive decay in which an unstable nucleus emits an alpha particle (a helium nucleus), resulting in the loss of $2$ protons and $2$ neutrons.

Beta Decay

A form of radioactive decay in which a nucleus releases a beta particle (an electron) as a neutron transforms into a proton, maintaining the same atomic mass while increasing the proton count by $1$.

Gamma Decay

A radioactive process in which an excited atomic nucleus releases energy in the form of gamma rays to become stable, keeping the same mass and number of protons.

Nuclear Fission

The process where a free neutron slams into a large, unstable nucleus, splitting it into smaller, more stable elements and releasing a massive amount of energy.

Fission Chain Reaction

A continuous sequence of nuclear reactions occurring when neutrons ejected during the fission of an unstable nucleus strike adjacent large nuclei, causing them to undergo fission as well.

Trinity Test

The famous second test of a plutonium fission bomb loaded with $13\text{ pounds}$ of Plutonium, which released explosive energy equivalent to $21{,}000\text{ tons}$ ($42\text{ million pounds}$) of TNT.

Atomic Radius

The width from the center of an atom to its outer edge, which depends on the number of protons and the number of electron shells.

Ionization Energy

The energy required to remove an electron from an atom, primarily determined by how close the atom is to achieving an octet and its atomic size.

Electronegativity

The tendency of an atom to attract and hold onto electrons more strongly than other atoms, following the exact same periodic trend as ionization energy.