Section 4.1 Atoms and Ions

Ion: an atom which has become charged by gaining or losing one or more electrons.

Trends in Periodic Table: Ability to Lose Electrons Decreases as you move across a period

Trends in Periodic Table: Ability to Gain Electrons Increases as you move across a period Stronger nuclear charge as the number of orbits stays the same but number of protons increase.

Definitions Cation: An atom that loses electrons and becomes positively charged. Anion: An atom that gains electrons and becomes negatively charged.

Rules for Bohr-Rutherford IONS 1. Calculate p+ and n0 just as you did for neutral atoms. 2. When determining the number of electrons add or subtract according to the charge given. If the charge is positive subtract, if it is negative add electrons! Example: 16 O -2 8

Summary of Ions: Electrons lost or gained lie on the valence shell (outer most shell) If there are less than 4 electrons in an atom’s valence shell it prefers to loose these electrons. If there are more than 4 electrons in an atom’s valence shell it prefers to gain the remaining electrons to have a full octet.

What does Na look like? What does Na 1+ look like?

Na and Na 1+

Fluorine: Bohr-Rutherford and Naming Draw a Bohr-Rutherford Diagram of Fluorine Draw its ion Note: “-” ions get an “ide” ending

Draw the ionic form of first 20 elements ( Bohr Rutherford diagrams WS) +1 +2 +3 +/-4 -3 -2 -1