1. 1/19 Work on the warm up while I take roll… Write out the formulas for the following compounds: aluminum sulfide potassium chlorate ammonium nitrate tin (IV) oxide REMINDER: “If your cat took chemistry” project due next Monday

2. Take a few minutes and look over your notes for the quiz – it contains all 3 types

3. PROPERTIES OF IONIC COMPOUNDS AND METALS Ionic and metallic bonding

4. Ionic bonding What elements electron configuration do all elements want to achieve?  Noble gases Na [Ne] __Na + [Ne] Cl [Ne] __ __ __ __Cl - [Ne] __ __ __ __ An ionic bond occurs when 2 oppositely charged ions come together to form a solid known as an ionic solid, also known as a salt It is generally between a metal and a nonmetal 3s 3p3s3p

5. Why does this happen? Which element has a higher electronegativity, Na or Cl?  Cl, same shielding, more “nuclear strength”  Na = 0.9 Cl = 3.0 In the following pairs, pick the element with the higher electronegativity value: Mg or O N or K Ca or Br

6. Ionic bonding Which grouping of elements have the higher electronegativity values? Nonmetals So nonmetals are more likely to ________ electrons in an ionic bond, and metals are more likely to ________. Oxidized = loses electrons, cation Reduced = gains electrons, anion LEO goes GER

7. Ionic Bonding The greater the difference in electronegativity values, the more ionic the bond is Which compound would have the greater ionic bond: magnesium oxide or barium fluoride

8. Ionic compound structure Ions pack together into a crystal lattice structure based on the ratio given by the formula Which ion is the larger one, Na + or Cl - ? The smallest part of this crystal is known as a formula unit Cl - Na +

9. Energy and the ionic compound When an ionic compound forms, it is always exothermic  Energy is released What are some signs that ENERGY is being released?  Light, heat, sound The energy of a compound is lower (more stable) than the ions separately

10. Why do you not throw a hair dryer in the bathtub? Does all water conduct electricity? Is tap water only made up of water molecules? Will salt water conduct electricity?

11. what holds everything together?: Inter vs. Intra What does an interstate do? – Connects one state to another Intermolecular forces connect one molecule to another What are intramurals? – Sports that are played within the school Intramolecular forces are within the molecule, connecting one atom to another Na Cl Na Cl

12. Why does salt water conduct electricity? When salt is mixed with water, it dissolves AND dissociates into its ions dissociates – The intramolecular forces are broken apart (as well as the intermolecular forces) This dissociation allows for the electrons to move more freely What is electricity? – The movement of ELECTRONS Do all ionic compounds conduct electricity?

13. 1/20 Work on the warm up while I take roll… Write out the formulas for the following compounds: aluminum sulfide hydrosulfuric acid ammonium nitrate tin (IV) oxide REMINDER: “If your cat took chemistry” project due next Monday

14. Quiz redo To earn up to half of your points back, do the following: Correct all missed questions, use a different color on the quiz sheet Type up a one page, double spaced, name only at the top, size 12 Times New roman font paper describing how to recognize, name and write formulas for each type of compound DUE TOMORROW AT THE BEGINNING OF CLASS!

15. Magnesium metal How can we tell that an ionic compound is forming? What is the magnesium reacting with (in order to burn)? What compound forms?

16. Does sugar water conduct electricity? Dissolves, but does not dissociate  No ions = No free moving electrons = no conducting Just the intermolecular forces are broken

17. Does salt conduct electricity? When salt is in its solid form, the electrons can not move Ionic compounds can only conduct electricity when dissolved in water, or in a molten state, this is known as an electrolyte

18. Have you ever seen salt melt? Sodium chloride has a melting point of 801 o C When something melts, what is the change in phase? – Solid to liquid In which phase are particles more strongly held together? – Solid So, if a substance has a high melting point, what can be said about the intermolecular forces– strong or weak? – Strong – it takes more energy to break them apart

19. Lattice energy The energy required to separate 1 mole of ions of an ionic compound (to break up the crystal lattice) Lattice energy is a negative value  Since the formation of an ionic compound gives off energy, this is the energy that is going back in  More negative = higher energy Energy is affected by size and value of charges of ions Which do you think would be a stronger hold – smaller or larger ions? LiCl vs KCl

20. Lattice energy Ions with higher charges have higher lattice energy KFvsMgO +1 -1+2 -2 - 808 kJ/mol - 3795 kJ/mol How do you think lattice energy affects melting/boiling point?  The higher the lattice energy the _____________ the melting point Which will have the higher melting point in the following: KBr vsNaBrCaSvsCaCl 2 SrCl 2 vsAgCl

21. Why are salts so hard and brittle? break stress applied Strong attractive forces hold ions in place, until a strong enough force is applied

22. “Sea of electrons” Metallic bond: attraction between delocalized (free floating) electrons and positive ions holds metal together Why are metals such good conductors?

23. Malleable and ductile The positive ions are shielded from each other by the sea of electrons, allowing the metal to be bent and drawn into wire

24. Strength and melting point As the number of delocalized electrons increases, so does the hardness/strength of the metal Transition metals have their d-block electrons that can move around Which metals have only 1 delocalized (valence) electron?  Alkali metals – very soft metals

25. Alloys Examples of alloys: brass (Cu and Zn) bronze (Cu, Zn and Sn) Any others you know of? Sterling silver, steel, gold jewelry Mixture of 2 or more elements that have metallic properties * not chemically bonded

26. We have discussed properties of both ionic bonding and metallic bonding In your groups, come up with some similarities and differences between the two

27. Take about 10 minutes and complete the Analyze and Conclude section of the lab Underneath this section, I would like you to write about 4-5 complete sentences which briefly explains the purpose of the lab, what happened during the lab, and how you know you did or did not form an ionic compound.