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Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda Go over Sec. 5.1 Quiz ...

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Page 1: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.
Page 2: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.
Page 3: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Thursday, Jan. 16th: “A” DayFriday, Jan. 17th: “B” Day

AgendaGo over Sec. 5.1 QuizFinish Section 5.2: “Ionic Bonding and Salts”

Properties of ionic compounds, crystal lattice, unit cell

In-Class: Sec. 5.2 review, Pg. 175: #1-10Homework:

“Positive and Negative Ions” worksheetConcept Review: “Ionic Bonding and Salts”

Page 4: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”This quiz seemed to give a lot of students

trouble so I wanted to take some time and go over it…

1.Which of the following electron configurations belong to an element that is the most chemically reactive?a. 1s2

b. 1s22s22p6

c. 1s22s22p5

d. 1s22s22p63s23p6

Page 5: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

2. An octet is equal to:a. 2b. 4c. 5d. 8

Page 6: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”3. How many valence electrons does the

element with the electron configuration 1s22s22p63s23p64s1 have?

a. 0b. 1c. 9d. 19

Page 7: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

4. Which of the following situations will cause the element with the electron configuration 1s22s22p5 to have an octet configuration?

a. Loss of one electronb. Gain of one electronc. Loss of two electronsd. Gain of three electrons

Page 8: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

5. Which of the following situations will cause the element with the electron configuration 1s22s22p63s2 to have an octet configuration?

a. Loss of one electronb. Gain of one electronc. Loss of two electronsd. Gain of three electrons

Page 9: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

6. The elements of Group _____ are able to satisfy the octet rule without forming compounds.

a. 1b. 2c. 17d. 18

Page 10: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

7. Stable ions of which of the following elements do NOT have octets of valence electrons?

a. Fb. Nac. Cld. Fe

Page 11: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

8. An element with the electron configuration 1s22s22p63s23p64s2 will ionize to a(n)

a. Anionb. Cationc. Noble gasd. Both (a) and (b)

Page 12: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

9. An element with the electron configuration 1s22s22p63s23p5 will ionize to a(n)

a. Anionb. Cationc. Noble gasd. Both (a) and (b)

Page 13: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5.1 Quiz: “Simple Ions”

10. An ion and its parent atom differ in

a. Electron configurationb. Number of electronsc. Chemical reactivityd. All of the above

Page 14: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Ionic CompoundsRemember, salts are electrically neutral ionic

compounds made of cations and anions.The ratio of cations to anions is always such that an

ionic compound has no overall charge.

=

Examples: Na+ + Cl- NaCl Mg2+ + O2- MgO

Page 15: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5 Properties of Ionic Compounds

1. Ionic compounds do not consist of molecules.2. Ionic bonds are strong.3. Ionic compounds have distinctive properties.4. Liquid and dissolved salts conduct electric

current.5. Salts are hard and brittle.

Page 16: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

1. Ionic Compounds Do Not Consist of Molecules

Water is a molecular compound, so individual water molecules are each made of two hydrogen atoms and one oxygen atom. (no ions involved)

Sodium chloride is an ionic compound, so it is made up of many Na+ and Cl ions all bonded together to form a crystal. There are no NaCl molecules, justNa+ and Cl- ions.

Page 17: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

1. Ionic Compounds Do Not Consist of Molecules cont…

Metals and non-metals tend to form ionic compounds and not molecular compounds.

The formula MgO likely indicates an ionic compound because Mg is a metal and O is a non-metal.

In contrast, the formula CO likely indicates a molecular compound because both C and O are non-metals.

Lab tests are needed to confirm such indications.

Page 18: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

2 Simple Rules to Tell if a Compound is Ionic or Covalent

Ionic Compounds:metal element + non-metal element

= ionic

Covalent Compounds:non-metal element + non-metal

element = covalent

Page 19: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

2. Ionic Bonds Are StrongAttractive forces exist between oppositely

charged ions and involve more than a single cation and anion.

Six Na+ ions surround each Cl ion and vice versa.As a result, the attractive force between

oppositely charged ions is significantly greater in a crystal than it would be if the ions existed only in pairs.

Overall, the attractive forces are much stronger than the repulsive ones, so ionic bonds are strong.

Page 20: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

3. Ionic Compounds Have Distinctive Properties

Most ionic compounds have high melting and boiling points because of the strong attraction between ions.

To melt, ions cannot be in fixed locations.Because the bonds between ions are strong, a

lot of energy is needed to free them.Still more energy is needed to move ions out

of the liquid state and cause boiling, so ionic compounds are rarely gases at room temperature.

Page 21: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Melting/Boiling Points of Ionic/Covalent Compounds

Page 22: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

4. Liquid and Dissolved Salts Conduct Electric Current

To conduct an electric current, a substance must satisfy two conditions:

it must contain charged particles

those particles must be free to moveIonic solids, such as salts, generally are not

conductors because the ions can’t move.When a salt melts or dissolves in water, the

ions can move around so they are excellent electrical conductors.

Page 23: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Sodium Chloride in 3 Phases

Page 24: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5. Salts are Hard and BrittleLike NaCl, most ionic compounds are hard and

brittle.Hard means that the crystal is able to resist

a large force applied to it.Brittle means that when the applied force

becomes too strong to resist, the crystal develops a widespread fracture rather than a small dent.

Both properties are due to the patterns in which the cations and anions are arranged in all salt crystals.

Page 25: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

5. Salts are Hard and Brittle cont…The ions in a crystal are arranged in a

repeating pattern, forming layers.If a force causes one layer to move, ions of the

same charge will be positioned next to each other.

This is why all salts shatter along a line extending through the crystal known as a cleavage plane.

Page 26: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

*How to Identify a Compound as Ionic*1. All ionic compounds are solids at room temp.2. Tap it gently: Ionic compounds are

hard/brittle and should not break apart easily. If it does break, it should fracture into crystals and not into a powder.

3. Heat it: Ionic compounds have high melting and boiling points.

4. Test conductivity: Ionic compounds are good conductors in liquid form.

5. Dissolve in water: Ionic compounds conduct electric current when dissolved in water.

Page 27: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Salt CrystalsDespite their differences, the crystals of all

salts are made of simple repeating units.These repeating units are arranged to form a

crystal lattice, the regular pattern in which a crystal is arranged.

These repeating patterns within a salt are the reason for the crystal shape that can be seen in most salts

Page 28: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Crystal Structure Depends on the Sizes and Ratios of Ions

Formulas indicate ratios of ions.For example, the formula for NaCl indicates

there is a 1:1 ratio of sodium cations to chloride anions.

Within a NaCl crystal, each Na+ ion is surrounded by six Cl ions, and each Cl ion by six Na+ ions.

Because the edges of the crystal do not have this arrangement, they are locations of weak points.

Page 29: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Crystal Structure Depends on the Sizes and Ratios of Ions

The arrangement of cations and anions to form a crystal lattice depends on the size of the ions and the ratio of cations to anions.

For example, the salt calcium fluoride, CaF2, has one Ca2+ ion for every two F ions.

The cations and anions in calcium fluoride also have a greater difference in size than those in NaCl.

Page 30: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Crystal Structure Depends on the Sizes and Ratios of Ions

Because of the size differences of its ions and their ratio in the salt, the crystal lattice structure of calcium fluoride (CaF2) is different from that of sodium chloride (NaCl).Each calcium ion is surrounded by eight

fluoride ions.At the same time, each fluoride ion is surrounded by four calcium ions.

Page 31: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

Salts Have Ordered Packing ArrangementsAll salts are made of repeating units. The smallest repeating unit in a crystal lattice

is called a unit cell.Unit Cell: the smallest portion of a crystal

lattice that shows the 3-dimensional pattern of the entire lattice.

The ways in which a salt’s unit cells are arranged are determined by X-ray diffraction crystallography.

Page 32: Thursday, Jan. 16 th : “A” Day Friday, Jan. 17 th : “B” Day Agenda  Go over Sec. 5.1 Quiz  Finish Section 5.2: “Ionic Bonding and Salts” Properties.

In-Class Assignment/HomeworkIn-Class:

Section 5.2 review, Pg. 175: #1-10Homework:

“Positive and Negative Ions” worksheetConcept Review: “Ionic Bonding and Salts”

You may work with a partner…

Quiz over Sec. 5.2 next time!


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