Definition:Iron
Chemical Element
Iron is the chemical element that has $26$ protons in the nuclei of its atoms.
Its chemical symbol is $\text {Fe}$.
Isotopes
$\text {Fe}$-$54$
Iron-$54$ is the isotope of iron which has $28$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$54$ is one of the $4$ stable isotopes of iron, forming $5.85 \%$ of the naturally occurring iron on Earth.
$\text {Fe}$-$55$
Iron-$55$ is the isotope of iron which has $29$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$55$ is radioactive, with a half-life of approximately $2.73$ years.
$\text {Fe}$-$55$ does not occur naturally.
$\text {Fe}$-$56$
Iron-$56$ is the isotope of iron which has $30$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$56$ is the most common of the $4$ stable isotopes of iron, forming $91.8 \%$ of the naturally occurring iron on Earth.
$\text {Fe}$-$57$
Iron-$57$ is the isotope of iron which has $31$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$57$ is one of the $4$ stable isotopes of iron, forming $2.12 \%$ of the naturally occurring iron on Earth.
$\text {Fe}$-$58$
Iron-$58$ is the isotope of iron which has $32$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$58$ is one of the $4$ stable isotopes of iron, forming $0.28 \%$ of the naturally occurring iron on Earth.
$\text {Fe}$-$59$
Iron-$59$ is the isotope of iron which has $33$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$59$ is radioactive, with a half-life of approximately $44.6$ days.
$\text {Fe}$-$59$ does not occur naturally.
$\text {Fe}$-$60$
Iron-$60$ is the isotope of iron which has $34$ neutrons in addition to its $26$ protons.
$\text {Fe}$-$60$ is radioactive, with a half-life of approximately $2.6 \times 10^6$ years.
$\text {Fe}$-$60$ exists on Earth as traces only.
Linguistic Note
The word iron is pronounced i-on. That is, the r is silent.
The symbol Fe used for iron derives from its Latin name ferrum.
