On Target? Do this on your Warm Up worksheet! Why does sugar dissolved in water not conduct electricity, while salt dissolved in water does conduct electricity? What is a dipolar molecule? Explain in complete sentences!

How salt dissolves

How sugar dissolves

For today 1.Warmup 2.Announcements 3.Big ideas Review 4.Chemical Bonds Objective: I can explain the 3 different types of bonds by describing how electrons are shared.

Announcement #1: FRESHMAN CLASS MEETING ON THURSDAY, FEBRUARY 25 TH IN MS. SHERWOOD’S ROOM (204) AT 2:20!

Semester Grades There was a problem in Skyward, so for some of your the grades on your report card are different than what your grades actually are on your transcripts! The ones that were different have been fixed, and if they did change you will be sent a new report card. Most changes should be a positive one, meaning your grade should go up! Some had a large difference, and others were a smaller difference-depending on how well you did on the final If you want to see what your grade is, see Ms. Benson/Ms. Klopfer in the attendance office and they can print off a transcript for you

Final! Presentation, model and group grades are all out of 100 points each Presentation grades were calculated to be made up of ¾ of your actual presentation and ¼ check-in and turning in on time with Ms. G Presentation and model grades multiplied in Skyward to be out of 450 points each Total with all 3 grades together in skyward was 1000 points The guest judges gave comments, but their imput did not affect your grade. My rubric has your grade in it, and I graded in red ink. Model grades are on the back! Models and user guides are ready to be picked up! If you don’t see yours, it’s in the library on display or I am keeping it for future examples (if you want it back, talk to me!)

Big ideas In your notebook: Fill in the following sentences 1.Charges are important because________________. 2.Water is attracted to both positive and negative objects because_________________________. 3.Water can dissolve objects with charges by _________________________. 4.Salt can conduct electricity in water because ____________________. Sugar cannot conduct electricity in water because _________________. Objective: I can explain the 3 different types of bonds by describing how electrons are shared.

Do you think electricity is conducted the same through a solution? What might be different about the atoms in metals vs. solutions? Ions-atoms with a positive or negative charge Electrolytes-substances that produce ions in water Example) Table salt (NaCl)

Bond Types Blue means to WRITE IN YOUR NOTEBOOK! Objective: I can explain the 3 different types of bonds by describing how electrons are shared.

Now think small…. Sketch this picture in your notebook. See if you can label any of the parts.

EXPLORE: Particular Properties electron proton neutron negative(-) positive(+) neutral Particle (Atom)

Why do atoms need to bond? Valence electrons (outer shell) Atoms are most stable with a full outer shell (8 electrons) Objective: I can explain the 3 different types of bonds by describing how electrons are shared.

3 types of bond Ionic Polar covalent Covalent What is the difference between these bonds? Objective: I can explain the 3 different types of bonds by describing how electrons are shared.

Ionic bonds: Electron transferred What are these? Makes separate charged particles called IONS

Polar Covalent Bonds Sharing electrons but unequally Means partial charge Electrons pulled more toward oxygen than hydrogen Makes one particle with both charges

Covalent bonds Sharing electrons equally Makes one particle with no charge

Categories on data table! What type of bond is table salt? – What other substances share properties with salt? What type of bond is sugar/glucose? – What else shares these properties?

Summary questions What is the charge on unbonded atoms? The charge on unbonded atoms is _______ Why does chlorine have a negative charge when ionically bonded to sodium? Chlorine has a negative charge when ionically bonded to sodium because ______________________ WHY DOES SALT NOT CONDUCT ELECTRICITY AS A SOLID BUT DOES IN SOLUTION?

IONS CAN MOVE!! How is that related to conducting electricity?

SUMMARY In a conductor, charged particles called ions (+ or – charge) are moving in an electrical current. For example, salt water must have ions moving between the prongs conducting electricity and so completing the circuit, lighting the LED lights. Sugar in water is a insulator because ions do not move so no electricity is conducted.

Why these different types of Bonds? Electronegativity: How much an atom can pull electrons Like a tug-of-war. If they are equally matched, they share the electrons equally. If one is way stronger, it can pull electrons away from another atom.

Partner Read p What does it mean when something is an electrical conductor? Partner A Partner B Reads paragraph Listens, asks questions Both write down bolded words and agree on their meanings. SWITCH ROLES WITH EACH PARAGRAPH.

ON YOUR OWN Write a summary (with an example) explaining... What does it mean when something is an electrical conductor? – Why would some of our solutions conduct electricity and others not? TURN INTO BASKET

Notes: If it is blue write it (or draw the diagram if the blue is to sketch). Title: WHY SOLUTIONS CONDUCT ELECTRICITY

To think about … How big is the nucleus of an atom compared to the whole atom? Why don’t atoms pass through one another? Why are you hovering cm above your chair right now? WHY IS THIS IMPORTANT?

Attraction and repulsion: One of the probes on conductivity meter is positive while other is negative Opposite charges attract! Ions move in solution toward the opposite charged probe (in salt water, Na+ moves toward –probe; Cl- moves toward +probe) This movement conducts electricity!

Diagrams on pg Copy the picture of the conductivity meter in the solution on page 112. What solution do you think this is? What are the + ions and – ions? 2.Label all the parts of the system. 3.Explain why the light is on in this picture. 4.Which figure on pg. 113 is water and which is baby oil? Use evidence to explain your answer.