Ions

• An ion is an atom or molecule that has a net electrical charge.
• The ionic charge of an ion is the charge of the ion and its magnitude is the number of electrons gained or lost by the atom.
  • cation: positively charged ion (lost electrons)
  • anion: negatively charged ion (gained electrons)
• The ion charge is written as a superscript after the chemical symbol.

monatomic ions

cation	name
$\mathrm{Na}{}^{+}$	sodium ion
$\mathrm{Al}{}^{3+}$	aluminum ion
$\mathrm{H}{}^{+}$	hydrogen ion
$\mathrm{Li}{}^{+}$	lithium ion
$\mathrm{K}{}^{+}$	potassium ion
$\mathrm{Mg}{}^{2+}$	magnesium ion
$\mathrm{Ca}{}^{2+}$	calcium ion
anion
$\mathrm{Cl}{}^{-}$	chloride ion
$\mathrm{I}{}^{-}$	iodide ion
$\mathrm{O}{}^{2-}$	oxide ion
$\mathrm{S}{}^{2-}$	sulfide ion

polyatomic ions

• the cation is named before the anion

ion
$\mathrm{H}{}_3\mathrm{O}{}^{+}$	hydronium	הידרוניום
$\mathrm{NH}{}_4{}^{+}$	ammonium	אַמּוֹנְיוּם, אַמּוֹן
$\mathrm{NO}{}_3{}^{-}$	nitrate	ניטראט, חַנְקָה
$\mathrm{SO}{}_4{}^{2-}$	sulfate	סולפט, גופרה
$\mathrm{OH}{}^{-}$	hydroxide	הידרוקסיד
$\mathrm{CN}{}^{-}$	cyanide	ציאניד
$\mathrm{PO}{}_4{}^{3-}$	phosphate	זַרְחָה, פוספט
$\mathrm{CO}{}_3{}^{2-}$	carbonate	קרבונט
$\mathrm{HCO}{}_3{}^{-}$	bicarbonate	ביקרבונט, מימן פחמתי
$\mathrm{CH}{}_3\mathrm{COO}{}^{-}$ (or $\mathrm{C}{}_2\mathrm{H}{}_3\mathrm{O}{}_2{}^{-}$)	acetate	אצטט