PPP- Notes #4a
Guided Notes 4a
Bonding (Polyatomic Ions)
*you NEED your Polyatomic
Reference Sheet to understand where the names are coming from*
Go with this example…
• Pretend Mrs. Shorette is a CATION (has energy/electrons to GIVE). She has 1 valence electron because she is from Group 1.
• Rancho High School is an ANION (needs to TAKE electrons to be stable). Rancho needs 2 valence electrons (two sets of classes) because they are from
Group 16.
• Mrs. Shorette cannot make an IONIC BOND with
Rancho High School’s needs. Welcome back Chemistry classes! Come back home (room 1009) on Monday!
What blue color means
• Throughout the slides you will see BLUE text.
This text is additional information. You may add this information to your notes if it will help you!
What are polyatomics?
• Polyatomics: ions made of a __groups of atoms__
• Example: ammonium __ (NH
4
)
• phosphate__(PO
4
) 3-
• Hint- we find out the names of the
(polyatomics) by looking at our Reference
Sheet
How are polyatomics used in ionic compounds?
• Some __can lose/give__ electrons like a metal and become a __cation__
• Example: ammonium (NH
4
) +
• Most __will take__ electrons like a nonmetal and become an __anion__
• Example: phosphate (PO
4
) 3-
How do you determine the formula using polyatomics?
• Cross-down method ( we find the charges of the polyatomics by looking at the Reference Sheet )
• (NH
4
) 1+ O 2_(NH
4
)
2
O_
(NH
4
) 1+ We find the 1+ on the Reference Sheet
O 2Like before, we use the Group # to tell us that Oxygen NEEDS to TAKE 2 more valence electrons to be stable/complete
Continued Example
• Na+ (PO
4
) 3__Na
3
(PO
4
)__
• Na 1+ Sodium is in Group 1 and wants to
GIVE away its 1 valence electron (you can just put a + to represent 1+)
• (PO
4
) 3We find the 3on the Polyatomic
Reference Sheet
How do you name these compounds?
• Positive ion is __1 st __
• Negative ion is __2 nd __
• “ide” ending __not used_ if elements are in brackets, then see Reference Sheet
• Note- Polyatomic name replaces the original ending.
Example (for naming)
• Sodium phosphate: Na
3
(PO
4
)
• Na
3 is Sodium
• (PO
4
) because it is in parenthesis we look at our Reference Sheet and find the name
Check for Understanding
*Use your flow chart on the
Reference Sheet*
• What is the name of Mg(SO
4
)
_Magnesium _ _Sulfate_
What is the name of (NH
4
) Cl
_Ammonium_ _Chloride_
Add to the bottom of your notes:
• Anytime you see ( ) they represent a polyatomic ion= check your table for their charge
