Atoms of the same element can exist with different numbers of neutrons, called isotopes. Isotopes are written with the element symbol and mass number, such as C14 for the carbon isotope with 6 protons and 8 neutrons. Ions are atoms that have gained or lost electrons, giving them a positive or negative charge and making them no longer neutral. Atoms gain electrons to become negative ions and lose electrons to become positive ions.

2.  Isotopes
 Atoms of the same element can have
different numbers of neutrons; the
different possible versions of the atom
of an element are called isotopes
 Written as a symbol and a number i.e.
C 14 is an isotope of carbon called
Carbon 14

4. Ions
▪An atom with a positive or
negative charge (temporarily
losing or gaining an electron)
▪Atoms are neutral unless they are
bonding

5. Ions
▪Atoms which gain electrons will
have a negative (-) charge and
become negative ions.
▪Atoms which lose electrons will
have a positive (+) charge and
become positive ions.