CHEM 1151 Lecture 2: Unit 2 Notes (Covers Chapters 4-6)

29 views5 pages
9 Oct 2018
School
Department
Course
Unit 2 Notes
Chemical bonds
o Ionic bonds: bonds formed between positive and negative ions
High melting points
Conduct electricity in solution
Usually formed between metals and nonmetals
o Covalent bonds: bonds formed by atoms sharing electricity
Can be gases, liquids, or solids
o Valence electrons: the electrons in the outermost energy level
The only electrons that are involved in bonding
o Ions
Cations: positive ions; atoms that lose electrons
Usually metals
Anions: negative ions ;atoms that gain electrons
Usually nonmetals
Octet rule: atoms will gain or lose electrons in order to get 8 valence
electrons
Charges of ions based on PT location
Group
Valence e-
Gain/lose e-
Ionic Charge
1
1
lose 1
+1
2
2
lose 2
+2
13
3
lose 3
+3
14
4
tweener
varies
15
5
gain 3
-3
16
6
gain 2
-2
17
7
gain 1
-1
18
8
neither
0
Writing formulas of ionic compounds
o Write positive ion followed by negative ion
o Cross charges to give subscripts
o If the subscript is 1, drop it
o If more than 1 polyatomic ion is needed, use parenthesis around the polyatomic
ion, then use the subscript
o Reduce the subscripts (outside of the parenthesis) to lowest whole number
Polyatomic ions
NH4+1
ClO3-1
OH-1
NO3-1
CO3-2
PO4-3
Ions with a Roman Numeral
Copper (I or II)
Chromium (II or III)
Iron (II or III)
Cobalt (II or III)
Nickel (II or III)
Manganese (II or III)
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
Lead (II or III)
Tin (II or IV)
Naming ionic compounds
o Learn the names/forumlas and charges
o Give the name of the positive )if the positive ion has more than 1 charge, include
a roman numeral in the name)
o Give the name of the negative ion
If monatomic ion: usually ends in -ide
If polyatomic ion: usually ends in -ate
Prefix
Meaning
mono-
1
di-
2
tri-
3
tetra-
4
penta-
5
hexa-
6
hepta-
7
octa-
8
nona-
9
deca-
10
Naming covalent compounds
o Use a prefix and the name of the first element
o Use a prefix and the name of the second element
The second element ends in -ide
Do not use the prefix
CO2: carbon dioxide
P4O10: tetraphosphorus decoxide
S2Cl2: disulfur dichloride
Lewis Dot Diagrams/Lewis Strutures (LDD)
o Shows only the valence electrons
o LDD for compounds
o Steps:
i. Count total valence e- in molecule
ii. Show LDD for each diagram
iii. Determine CBA for each molecule
iv. Arrange LDD for atoms around the CBA so that single e-are next to each
other
v. Form bonds between atoms sharing e- one for each atom
1. Share 1 pair e- = single bond
2. Share 2 pair e- = double bond
3. Share 3 pair e- = triple bond
vi. Try to get 8 e- around each atom
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.