Get the definitions of cations and anions. See examples of the two types of ions, learn how they are different, and see periodic table trends.
Explore the differences between cations and anions, their roles in chemical reactions, and their placement on the periodic table. Learn more now.
In chemistry, cations are indicated with a plus sign (+) and anions are indicated with a minus sign (-), with the number of symbols indicating the number of electrons lost or gained (this is called an atom’s valence).
A sodium cation (Na⁺) and a chloride anion (Cl⁻) lock into place because of that charge difference. The strength of the bond depends on two things: the size of the charges and the distance between the ions.
Cations and anions are both ions, but they differ based on their net electrical charge; cations are positive, while anions are negative.
What's the difference between Anion and Cation? An ion is an atom or group of atoms in which the number of electrons is not equal to the number of protons, giving it a net positive or negative electrical charge.
TL;DR: Cations are positively charged ions (like Na+), while anions are negatively charged ions (like Cl-). They form when atoms gain or lose electrons, and they’re everywhere—from table salt to your body’s chemistry!
The chemical formula of a compound is always written with the cation first, followed by the anion. For example, Na is the cation and Cl is the anion in NaCl (table salt).
A cation is something that moves down (Greek: κάτω, kato, meaning "down") and an anion is something that moves up (Greek: ἄνω, ano, meaning "up"). They are so called because ions move toward the electrode of opposite charge.