1/19 Work on the warm up while I take roll…

• Write out the formulas for the following compounds:

aluminum sulfidepotassium chlorateammonium nitratetin (IV) oxide

REMINDER: “If your cat took chemistry” project due next Monday

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

PROPERTIES OF IONIC COMPOUNDS AND METALS

Ionic and metallic bonding

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 saltIt is generally between a metal and a nonmetal

3s

3s 3p 3s 3p

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 ON or KCa or Br

Ionic bonding

Which grouping of elements have the higher electronegativity values?

NonmetalsSo nonmetals are more likely to ________

electrons in an ionic bond, and metals are more likely to ________.

Oxidized = loses electrons, cationReduced = gains electrons, anion

LEO goes GER

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

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

isknown as a formula unit

Cl- Na+

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

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?

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

Na

Cl Cl

Na

Cl

Why does salt water conduct electricity?

• When salt is mixed with water, it dissolves AND dissociates into its ions– 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?

1/20 Work on the warm up while I take roll…

• Write out the formulas for the following compounds:aluminum sulfidehydrosulfuric acidammonium nitratetin (IV) oxide

REMINDER: “If your cat took chemistry” project due next Monday

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!

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?

Does sugar water conduct electricity?

Dissolves, but does not dissociate No ions = No free moving electrons = no

conducting

Just the intermolecular forces are broken

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

Have you ever seen salt melt?

• Sodium chloride has a melting point of 801oC

• 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

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

Lattice energy

Ions with higher charges have higher lattice energyKF vs MgO

+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 vs NaBr CaS vs CaCl2

SrCl2 vs AgCl

Why are salts so hard and brittle?

break

stressapplied

Strong attractive forces hold ions in place, until a strong enough force is applied

“Sea of electrons”

Metallic bond: attraction between delocalized (free floating) electrons and positive ions holds metal together

Why are metals such good conductors?

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

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

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

We have discussed properties of both ionic bonding and metallic bonding

In your groups, come up with some similarities and differences between the two

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.