Catalyst - PowerPoint Presentation

Slide1

Catalyst

1

. What

are the trends for ionization energy? Why do these trends exist?

2

. As you go across a period, do elements get better or worse at attracting electrons?

Justify

your response.

3

. As you go

down a group,

do elements get better or worse at attracting electrons?

Justify

your response

.Slide2
Slide3

Today’s Learning Targets

1.9 – I can define and calculate the effective nuclear charge for an atom and explain how this impacts observed periodic trends

.

1.11 – I can define ionization energy and explain how it relates to the effective nuclear charge. Furthermore, I can explain how this trend changes as you move throughout the Periodic Table and relate it to the elements quantum electron configuration.1.12 – I can define electron affinity and explain how it relates to the effective nuclear charge. Furthermore, I can explain how this trend changes as you move throughout the Periodic Table and relate it to the elements quantum electron configuration.Slide4

Ionization Energy

Ionization Energy

– The minimum energy needed to remove an electron from an element.Slide5

Elements Can Have Multiple Ionization Energies

The first ionization energy is the energy to remove 1 electron from a neutral atom:

Na

 Na

+ + 1 e-The second ionization energy is the energy needed to remove the 2nd electron from a charged atom:

Na

+

 Na

+2

+ 1 e

-

2

nd

IE > 1

st

IE

The IE increases as you remove more electrons because you are pulling an electron from a more positive atom.Slide6

Justify – TPS

Examine the ionization energies for silicon below:

Why is there a huge jump seen between IE

4

and IE5?

First

Ionization Energy (IE

1

)

786 kJ/

mol

IE

2

1577 kJ/molIE33232 kJ/molIE44356 kJ/molIE516,091 kJ/molSlide7

Periodic Trend for IE

IE

increases across a period

because there is a higher

Zef, so the nucleus holds onto the electron more tightlyIE decreases down a group because there is a lower Zef due to the fact that the electrons are further away from the nucleus.Slide8
Slide9

Class Example

Which of the colored elements on the Periodic Table below will have the highest

second ionization energy

?Slide10

Table Talk

The first ionization energy for nitrogen is 1402 kJ/mol. The first ionization for oxygen is 1314 kJ/mol. Oxygen is further to the right of nitrogen. Why does nitrogen have a higher first ionization energy?Slide11

Justify – TPS

Using electron configurations to defend your answer, explain which of the following processes is more favorable for fluorine:

F

 F

+ + e-F + e-

 F

-Slide12

Electron Affinity

The opposite of ionization energy is electron affinity.

This is the energy required to add an electron to an atom

Measures the attraction for the nucleus to the newly added electron

The greater the attraction between the atom and the added electron, the more negative the electron affinity value.E.g. Chlorine = -349 kJ/mol and Sodium = -53 kJ/molSlide13

Table Talk

Do you think neon will have a higher or lower electron affinity than fluorine? You must justify your response with evidence for full credit.Slide14

Trend for Electron Affinity

Elements that only need one (or two) electron to fill or “half” fill a subshell will have much higher electron affinities than element that already have a filled subshell.

Therefore, the only way to predict electron affinities is by examining the element’s electron configuration.

Electron affinities do not vary much as we go down a groupSlide15
Slide16

SummarizeSlide17

White Board RacesSlide18

Question 1

The electron affinities of five elements are given below:

Define

the term “electron affinity” of an atom.

For

the elements listed above, explain the observed trend with the increase in atomic number. Account for the discontinuity that occurs at phosphorus Slide19

Question 2

2. Use the details of atomic theory to explain each of the following experimental observations.

a

. Within a family such as the alkali metals,

the ionic radius increase as the atomic number increases.Slide20

Question 3

3.

Use the details of atomic theory to explain each of the following experimental

observations:

b. The radius of the chlorine atom is smaller than the radius of the chloride ion, Cl-. (Radii:

Cl

atom = 0.99

Å

;

Cl

-

ion = 1.81 Å) Slide21

Question 4

4.

Use the details of atomic theory to explain each of the following experimental observations.

c

. The first ionization energy of aluminum is lower than the first ionization energy of magnesium (First ionization energies: 12

Mg =

7.6

ev

;

13

Al = 6.0

ev

)Slide22

Question 5

5. Use

the details of atomic theory to explain each of the following experimental observations

.

d. For magnesium, the difference between the second and third ionization energies is much larger than the difference between the

first

and second ionization

energies

.

(

Ionization energies for Mg: 1

st

= 7.6

ev; 2nd = 14 ev; 3rd = 80 ev)Slide23

Paper in WaterSlide24

Lab 3: Chromatography and Sharpies

Take down the following notes in your lab manual

These notes will help with your formal lab report on this labSlide25

Lab WorktimeSlide26
Slide27

Closing Time

Finish Chapter 7 and all corresponding problems to stay on task.

Lab report on Lab 3: Chromatography and Sharpies due September 4

th