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Catalyst (5 minutes). Draw electron dot structures for the following elements (find the number of valence electrons!) ON A SEPARATE SHEET OF PAPER (KEEP IT FOR THE WEEK):. 1. Chlorine. 3. Oxygen. O. Cl. 2. Carbon. 4. Nitrogen. C. N. Covalent Bonds. What we’ve learned so far….
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Catalyst (5 minutes) Draw electron dot structures for the following elements (find the number of valence electrons!) ON A SEPARATE SHEET OF PAPER (KEEP IT FOR THE WEEK): 1. Chlorine 3. Oxygen O Cl 2. Carbon 4. Nitrogen C N
What we’ve learned so far…. • Atoms lose/gain electrons to form cations and anions (8 valence electrons like a noble gas!) • Charged anions and cations form IONIC BONDS to make IONIC COMPOUNDS - K F +
What we’re learning today… • Atoms can also SHARE electrons to form COVALENT BONDS! • Why is this important? • Covalent bonds are important in many organic molecules (living creatures) • Examples: • Cell membranes are made of lipids (We’d be puddles of liquid without them!) • Proteins (We’d starve without them!)
Covalent Bond • The chemical bond formed when two atoms SHARE electrons • Why do atoms form bonds? To gain the same number of valence electrons as a noble gas! Cl Cl Full octet (8)! Full octet (8)! Bonding Pair
Types of Covalent Bonds • Single Bond: ONE pair of shared electrons • Double Bond (Pi Bond): TWO pairs of shared electrons • Triple Bond: THREE pairs of shared electrons Cl Cl O O N N
How many bonds can an atom form? • # bonds formed = # of UNPAIRED electrons • # electrons atoms keep = # electrons in PAIRS 3 unpaired electrons N N = 3 bonds! O 2 pairs = four electrons the atom keeps!
Example 1 • How many bonds can Sulfur form? • How many electrons will Sulfur keep to itself? Two unpaired electrons! S Two bonds can be formed! Two pairs of electrons! S Four electrons will be kept by sulfur!
Example 2 • How many bonds can Carbon form? • How many electrons will Carbon keep to itself? Four unpaired electrons! C Four bonds can be formed! No pairs of electrons! C Zero electrons will be kept by carbon!
Example 3 • How many bonds can Neon form? • How many electrons will Neon keep to itself? Zero unpaired electrons! Ne Zero bonds can be formed! Four pairs of electrons! Ne Eight electrons will be kept by neon!
Announcements • Homework – Due Fri Feb 4 • Read Sec 8.1, pp 240-247 • Define vocab on p 240 (7 words) • Choose any 3 of the words and draw an illustration to show what they mean
Worksheet • COMPLETE the worksheet