9/22/10
Post date: Sep 21, 2010 7:40:29 PM
Bell Ringer: Compare and contrast ionic and covalent bonds
Atoms don't always share equally
When two different elements bond together, sometimes the electrons are more attracted to one nucleus than the other. This is called a polar covalent bond. (when electrons are equally attracted to each nucleus, we call it a nonpolar covalent bond)
Electrons are typically more attracted to elements that are farther to the right and higher up on the periodic table of elements.
Ionic and Covalent Bonding
Go over homework
I2
S2
H20
NH3
P2
Work on bonding practice worksheet (due tomorrow if not finished in class)
Metallic Bonds
Cross between ionic and covalent compounds
Atoms group together, similar shape to a network
Outer layers of electrons overlap, and are shared with neighbors
Electrons are shared between ALL atoms, and can flow freely
Metals conduct electricity and are flexible because their atoms and electrons can move freely throughout the metal's structure
Polyatomic Ions
Breaking down the word:
Poly = many
Atomic = made of atoms
Ion = body that has a non-zero charge
Molecules with a charge
Stick together as a group (behave like a single unit), can bond with other ions
Many common examples
NaHCO3 = baking soda
Na2CO3 = used to make soaps and cleaners
Oppositely charged polyatomic ions can bond together to make larger compounds
(NH4)2SO4
Use parentheses to separate a polyatomic ion from the rest