1. Section 6-3, p. 165 Section 7-1, pp. 180 - 184
Ions
Section 6-3, p. 165
Section 7-1, pp

2. How come atoms are neutral?
The number of protons (+) and electrons (-) is equal.
What happens when there is not an equal number of protons and electrons?
IONS

3. The structure of electrons in an atom gives the element its properties
Atoms are considered stable when their outer energy level (valence energy level) is full
Atoms with full outer shells are non-reactive
If their outer energy level is not full, atoms will react with one another in an effort to fill their outer shell.

4. Ions An ion is a charged (positive or negative) atom.
Ions are formed when atoms gain or lose electrons.
The number of protons and neutrons in the atom stays the same.
An atom that loses electrons becomes POSITIVE and is called a cation.
An atom that gains electrons becomes NEGATIVE and is called an anion.
Atoms will lose or gain electrons depending on how many are in their valence energy level.
The atom will do whatever is easiest.

5. Forming Cations
If an atom loses electrons it becomes positively charged.
Electrons are negative, so removing them leaves more positive protons.
Positive ions are called CATIONS.
The chemical symbol with a plus sign next to it shows that the atom is a cation.
Ex: Lithium, Li+

6. Forming Anions
If an atom gains electrons it becomes negatively charged.
Electrons are negative, so gaining them creates a negative charge.
Negative ions are called anions.
The chemical symbol with a minus sign next to it shows that the atom is an anion.
Example: Flourine, F-

7. What type of element tends to form anions?
What type of element tends to form cations?

8. Non-metals metals What type of element tends to form anions?
What type of element tends to form cations?
Non-metals
metals