Some Atoms Form Ions

1. Some Atoms Form Ions • ionization = the process of adding or removing electrons from an atom or group of atoms • Atoms that do not have filled valence shells may undergo ionization • ion – a charged atom (a neutral atom has lost or gained one or more e-)

2. If the atom gains or loses electrons, it no longer is neutral (ie, the # p+ and # e- are not the same) Cation - positively charged ion (less electrons than protons) Ex: Lithium has 3 e- and is very reactive Removing the e- makes lithium less reactive It now has a full valence shell Lithium ion written as Li+ It is not helium because we determine element by amount of protons (Helium has 2 e- like the Li + ion) It is not lithium…..it is a lithium ion!

3. Naming a Cation: uses the name of the parent atom Ex: Na+ is called Sodium ion Mg2+ is called a magnesium ion (charge of +2) Al 3+ is called an aluminum ion (charge of +3)

4. Anion – negatively charged ion (more electrons than protons) Ex: Fluorine has 9 e- and is reactive (7 e- in valence shell) Adding the e- makes fluorine less reactive because it now has a full valence shell fluorine ion written as F- It is not neon (Ne has 8 e- like the F-ion) It is not fluorine ….it is a fluorine ion!

5. Naming a Anion: use the root name of the atom and change the ending to have the suffix “ -ide” Ex: F - is called Fluoride ion I - is called an Iodide ion O 2- is called an oxide ion (charge of -2)

6. Quiz on Monday! Here are the topics: Info about energy levels, shells, orbitals Orbitals vs. orbits Electron info (symbol, charge, property) Mass comparison of p, e, n Niels Bohr and the Bohr model for 1st 18 elements Valence electrons and valence shell Relationship of period and columns with electrons and valence electrons Rule of octet Shell names and maximum amount of electrons Subshell names and maximum amount of electrons How to name subshells of 1st 18 elements Nuetral atom, Ion, cation and anion information