This preview shows page 1. Sign up to view the full content.
Unformatted text preview: Unit B
1. Ions – charged species. ( rearrangement of e’)
anions- negative Octect Rule
Noble gasses are extra stable because they have eight valence e’. The p orbitals are filled.
All other elements want to achieve the noble gas e’ configuration. Positive ions- 2e Mg 12 p 12 e' 8e 2e 2e 1s22s22p63s2 1s22s22p6
Same as Ne Na loses 1 e’ to become Na+ 1s22s22p63s1 --------- 1s22s22p6 + 1e’ 1 Negative Ions- 2 e' 2e 8e 6e 2e S 16 p 16 e'
Same as Ne N gains 3e’ to become N3- 1s22s22p3 + 3e’ -------- 1s22s22p6 Group number will determine the number of electrons given up or accepted
-1 Metals take on positive charges, Non-metals negative charges
Examples H+ Be2+ Al3+ N3- S2- Cl- Exception is H that can be H+ or H-, in water H+ = H3O+
2. Ionic Compounds – metal (left of periodic table, positive) + non-metal (right of
periodic table, negative)
Positive and negative ions come together to form a compound. Ionic bond.
Physical properties- usually form solid crystals and are poor conductors. 2 Ex.
:Br: + Æ K+ + Br- Æ KBr Æ Mg2+ + Cl- Æ MgCl2 Æ Al3+ + Cl- Æ AlCl3 . Ca: ..
:F: + . .
. + Write subscripts when doing ionic compounds they do not change. Two wheels per bike. 3. Covalent Compounds- sharing of e’, two non-metals
Look at Cl each atom want one more e’, neither wants to form a positive charge. l
C + l
C Diatomic- X2, other diatomic molecules Group 7 (F2,Cl2, Br2)and N2, O2 H2
Look at NH3 3 H
N H + H N H H
H Covalent bonds- Non-metal, non-metal
Group Number Valence e’ 1
7 Covalent bonds
1 Must full fill octet
O H + H O H H C + Cl
C C l
C Can have multiple bonds. 4 Ex. CO2
: :: : OCO Ex. C2H2
HC CH 4. Exceptions to the octet.
a. : : O : :: :
NO : NO2
O NO : b. The filling of D orbitals
F FF F
F 10 e' 12 e' c. Fewer than 8 e’.
F Be F
4 e' FF
6 e' 5. Polarity- only with covalent bonds. (two non-metals)
Polar if unequal sharing on electrons, a net dipole moment, unsymmetrical e’
cloud. F F share equally
F F H F share un-equally
d+ dH F Depends on electronegativity- amount an element attracts e’ pairs. (look at
periodic table) F has the highest at 4.0. C H bonds are declared non-polar. 5 Ex. C-Cl
d+ d- C Cl 6. Metallic bonds- attraction between negative and positive metal ions delocalized
metals combine to form a sort of mixture- properties dependent on concentration.
Brass- Cu and Zn
Bronze- Cu and Sn
One or more elements is an alloy. 6 ...
View Full Document
This note was uploaded on 09/02/2011 for the course CHEM 2 taught by Professor Harrison during the Spring '11 term at West Valley.
- Spring '11