Let’s Get Ready for the Test!

Use the powerpoint with your “Study Guide”Try to answer each slide.

THEN, Click on the next to get the answer and some notes!

A. Are these Ionic, Metallic, Covalent, or Network Covalent?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

A. Answers M Cu C_ NH3

I MgCl2

C CO2

NC C - DiamondI MnO2

C CH4

I CaBr2

Why?Only metal- metallicOnly non-metal – covalentMetal and non-metal - ionic

B. Polar (P) or non-polar (NP)?Water

Paint thinner

N FF

F

C FF

F

FO

HH

C OO

B. AnswersWhy? Asymmetrical = polar Symmetrical = non-polarP Water

NP Paint thinner

N FF

F

C FF

F

FO

HH

C OONP

NP

P

Physical PropertiesHow things LOOK or ACT

C. Which is brittle and conduct only when liquid or dissolved in water?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

C. Answers

MgCl2

MnO2

CaBr2

Why?Ionic compounds are brittle (like salt) and conduct when dissolved in water

Metals are shiny and bendable

Network covalent (diamond) are very hard and not brittle

Other covalents are usually gases or liquids at room temperature

D. Which is malleable (bend easily) and conduct electricity?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

D. AnswersCu

Metals bend easily

Metals always conduct because they have a “sea of electrons” around them

(Each metal atom is trying to give up it’s electrons to the others so the electrons flow from one to the next.)

E. Which will dissolve in polar solvents like water?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

C OO

C HH

H

H

N HH

H

E. AnswersNH3

MgCl2

MnO2

CaBr2

N HH

H Why? “like dissolves like” (polar dissolves polar)Polar covalent AND ionic compounds dissolve in polar solvents like water

(Ionic can be thought of as extremely polar)

SolubilityThe ability to dissolve.

Dissolving always involves the mixing of two different substances.

When a substance dissolves it breaks up and spreads out into the other substance.

F. Which will dissolve in non-polar solvents like paint thinner?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

C OO

C HH

H

H

N HH

H

F. AnswersCO2

CH4C HH

H

H

C OO

“like dissolves like”Non-polar dissolves non-polar

Non-polar covalent dissolve in non-polar solvents like paint thinner.

Metals and network covalent (diamond) do not dissolve in anything

ConductivityThe ability to conduct electricity.

Electricity is moving electrons – the valence electrons are transferred from one atom to the next, to the next, and so on.

G. Which will always conduct electricity (when solid or liquid)?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

G. AnswersCu

Metals always conduct electricity because of the atoms are surrounded by a “sea of electrons”

Each metal atom is trying to give away it’s valence electrons but no atom wants them.

They pass them down the line!

H. Which will conduct electricity when liquid or dissolved?CuNH3

MgCl2

CO2

C - DiamondMnO2

CH4

CaBr2

H. AnswersCuMgCl2

MnO2

CaBr2

Why? Electricity is moving electrons

Metals conduct (sea of electrons)

Ionic compounds conduct when liquid (dissolved or melted) – the metal is trying to give away it’s electrons so they move

Covalent never conduct (they share electrons and shared electrons don’t move)

Melting PointThe temperature when something goes from

a solid to a liquid.

Substances with higher melting points can support more heat before turning to liquids.

Turning from solid to liquid means the atoms have broken free from their position and can flow.

I. Number these “1, 2, 3, 4, or 5”1 = highest melting point5 = lowest melting point

CuNH3 and H2O

MgCl2 and MnO2 and CaBr2

CO2 and CH4

C - Diamond

I. Answer – Highest (#1)

C – Diamond

Each atom is bonded to every other atom with covalent bonds. This makes it SUPER strong – strong means it will have a SUPER HIGH melting point.

Answer – next highest (#2)MgCl2 and MnO2 and CaBr2

Ionic bonds are strong because they form crystals of opposite charges.Strong bonds means high melting point

Answer -3rd highest (#3)?Cu

Why?Metals are solid at room temp so they must be heated to melt.

Answer -4th highest (#4)NH3 and H2O

N HH

H

Why? Polar molecules have a positive and negative end so they are “sticky” and hold on to each other to stay solid a little longer

Answer- Lowest (#5)

CO2 and CH4C OO

C HH

H

H

Why? Non-polar covalent molecules have no charge and so they cannot “hold hands” to stay together.