Atomic Structure
Isotopes and Ions
To explain how isotopes and ions differ from neutral atoms and how each is formed.
What you will learn
What makes atoms of the same element isotopes
How isotopes differ in their neutron numbers
How atoms become ions by gaining or losing electrons
Why forming an ion does not change the element
How to identify isotopes and ions from particle numbers
Explanation
Isotopes are atoms of the same element with equal proton numbers but different neutron numbers. An ion forms when an atom gains or loses electrons, changing its charge without changing the element. Losing electrons makes a positive ion; gaining electrons makes a negative ion. Nuclear numbers do not change during ordinary ion formation. Example: Determine electrons in an ion with 12 protons and charge +2. It has lost two electrons, so electrons = 12 − 2 = 10. Use clear labels. Explain the result.