Unit 3: Chemical Bonds

Unit 3: Chemical Bonds

Open Ended

9/23/2020

What are the 3 subatomic particles found in an atom? what are the charges of these particles?

Why do atoms form bonds?

• To complete their outer shell (octet: 8 valence electrons)

• To become more stable

Multiple Choice

Which family on the periodic table has a complete octet?

• Alkali Metals

• Alkaline Earth Metals

• Transition Metals

• Halogens

• Noble Gases

How are bonds formed?

• A chemical bond forms when atoms transfer or share e-

• Three Types: 

• ionic, covalent, metallic
  
  

Ionic Bond

• e- are transferred

• involves ions (metal and nonmetal elements)

Ionic Bond

• Metals lose their valence e- and become cations (+)

• Nonmetals gain those e- and become anions (-)

Ionic Bond

• Metals lose their valence e- and become cations (+)

• Nonmetals gain those e- and become anions (-)

Multiple Choice

Which of the following elements would LOSE electrons?

• Na

• Cl

• F

• S

Multiple Choice

Which of the following elements would GAIN electrons?

• Be

• Cl

• Li

• K

NaCl

• Na is a metal therefore it's going to LOSE its outer e-

• Cl is a nonmetal therefore it's going GAIN the e-

NaCl

• Na LOST its 1 e- and became a cation (+)

• Cl GAINED 1 e- and became an anion (-)

Why do atoms become cations when they LOSE e-?

• More protons (+) than e- (-)

Why do atoms become anions when they GAIN e-?

• More e- (-) than protons (+)

Metals lose however many valence e- they have

• e- in the outermost shell

Multiple Choice

How many e- will Sodium lose?

• 1

• 2

• 3

• 4

• 5

Multiple Choice

How many e- will Aluminum lose?

• 1

• 2

• 3

• 4

• 5

Multiple Choice

How many e- will Magnesium lose?

• 1

• 2

• 3

• 4

• 5

Nonmetals GAIN however many valence e- they need to get to 8 

• Complete their octect (outermost shell)

Multiple Choice

How many e- does Fluoride gain?

• 1

• 2

• 3

• 5

• 7

Multiple Choice

How many e- does Oxygen gain?

• 1

• 2

• 3

• 5

• 7

Multiple Choice

How many e- does Phosphorus gain?

• 1

• 2

• 3

• 5

• 7

Complete Ions Table assignment

Open Ended

Phosphorus

(valence e-, metal or nonmetal, gain or lose e-, cation/anion, symbol and charge)

Lewis Dot Structures

LDS

For today you need...

• Paper/ notebook

• Writing utensil

• Periodic Table

LDS

• show only the valence e- (outer e-)

• Begin on the right and go counterclockwise

• Each side gets 1 valence e- before doubling up

Draw the LDS for the following elements:

• 1. Helium

• 2. Fluorine

• 3. Nitrogen

LDS for ionic compounds

metal (+) and nonmetal (-)

Multiple Choice

What is happening to the electrons in an ionic bond?

• They are being transferred

• They are being shared

Multiple Choice

In an ionic compound, do metal elements lose or gain e-?

• Metals lose e-

• Metals gain e-

Multiple Choice

When metals LOSE e-, they become...

• negative ions called anions

• positive ions called cations

• negative ions called cations

• positive ions called anions

Multiple Choice

In an ionic bond, nonmetal elements...

• lose e- and become cations

• gain e- and become anions

LDS for ionic compounds

• Draw LDS for each atom 

• Metal element(s) will lose valence-e

• Nonmetal element(s) will gain those e- to complete their octet

• Redraw LDS showing the transfer of e- and the ion charge

Ex 1)

• Draw the lewis dot structure for NaCl

Ex 2) MgO

Ex 3) 
Potassium Sulfide (K2S)

Open Ended

Exit Ticket: Using the whiteboard app, draw the following LDS:

1) LiF

2) Na₂O

3) BaO

How are bonds formed?

• A chemical bond forms when atoms transfer or share e-

• Three Types: 

• ionic, covalent, metallic
  
  

Covalent Bonds

• e- are SHARED (no ions or charges)

• nonmetal elements only

Covalent Bond

• nonmetal elements ONLY

• Ex: CO, H2O

Multiple Choice

Which of the following is covalent?

• KF

• NO₂

Multiple Choice

Which of the following is covalent?

• MgCl₂

• NH₃

Multiple Select

Select all of the COVALENT bonds

• NaCl

• CH₄

• CO₂

• Al₂O₃

• SF₆

LDS for covalent bonds

nonmetals share e-

• e- sharing is represented using a dash

• each dash represents 2 e- being shared

• Single bond: 2 e- shared

• Double Bond: 4 e- shared

• Triple bond: 6 e- shared

• Atoms will share e- in a way that completes their octet (8 valence e-)

• *EXCEPTION: H and He, they only need 2 valence e- to be stable!

Ex1) Draw the LDS for water

Step 1: Draw skeleton structure

• The atom that needs the MOST e- goes in the center

• *Hydrogen is never the central atom

Step 2: Draw each atom's LDS

• Pro-tip: use a pencil

Step 3: Connect (pair up) electrons

• Use a dash to indicate e- being shared

Step 4: Check octets

• All atom's should have a complete octet (8)

• e- being shared count for both elements

• *H and He (only need 2)

Open Ended

Draw the LDS for O₂

Metallic Bonds

• Metals ONLY

• e- are mobile 

• e- move freely through metal

• This is how electricity is conducted

• e- carry electric current when they move

Open Ended

Exit Ticket: Draw the LDS for the following:

CO₂

F₂

NH₃