Catalyst – February 8*3-2, 2.010* 10 3
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Transcript of Catalyst – February 8*3-2, 2.010* 10 3
Catalyst – February 8*3-2, 2.010* 103
Monday Mystery Element
Discovered by boiling urine
There are 2 forms: white and red
The white forms combusts in airDon’t forget to
make your Weekly Goal!
Catalyst – February 8*3-2, 2.010* 103
Monday Mystery Element
Discovered by boiling urine
There are 2 forms: white and red
The white form combusts in air
PHOSPHORUS!
Today’s Agenda
Catalyst More secrets of the PT: Valence
Electrons, Atomic Size, and Electronegativity
Group Work Time Exit Question
Today’s Objectives
SWBAT determine periodic trends for valence electrons, atomic size, and electronegativity.
Why do scientists use graphs?To organize, compare, and display experimental data
To make calculations and predictions
How to Graph
1. Label axes (x = ______, y = _______)
2. Title graph (y-axis vs. x-axis)3. Determine scales4. Plot each point5. Draw trend line (line of best fit)
Valence Electrons
Don’t forget!Valence electrons are the electrons in the outermost energy level.
Example
Electron configuration for silicon (Si): What is the highest energy level? So how many valence electrons?
1s22s22p63s23p2
2 + 2 = 4!
Group Challenge
Each group will write electron configurations for the elements in ONE family. Then, count the number of valence electrons for each configuration. Group 1: Alkali Metals Group 2: Alkaline Earth Metals Group 3: Boron’s Group Group 4: Carbon’s Group Group 5: Nitrogen’s Group Group 6: Halogens Group 7: Noble Gases Group 8: Noble Gases
Group Challenge
Each group will write electron configurations for the elements in ONE family. Then, count the number of valence electrons in each configuration. Group 1: Alkali Metals Group 2: Boron’s Group Group 3: Carbon’s Group Group 4: Nitrogen’s Group Group 5: Halogens Group 6: Noble Gases
Valence Electrons
What is Atomic Size?
Atomic size is… How big an atom is Also known as atomic radius
Graphing Atomic Size (Radii)Draw 2 line graphs
X-axis: Element Y-axis: Atomic Radius (picometers)
Elements and their Atomic Radii (1)
Element Atomic Radius
(picometer)
Hydrogen 37
Lithium 152
Sodium 186
Potassium
227
Rubidium 248
Cesium 265
1 picometer = 1 x 10-12 m Element Atomic
Radius (picomet
er)
Lithium 152
Beryllium
112
Boron 85
Carbon 77
Nitrogen 75
Oxygen 73
Fluorine 72
Neon 71
Atomic Size – Graph 1
0
50
100
150
200
250
300
350
0 1 2 3 4 5 6 7
Element
Ato
mic
Ra
diu
s (
pic
om
ete
r)
H Li
Na K Rb Cs
Atomic Size – Graph 2
0
20
40
60
80
100
120
140
160
0 2 4 6 8 10
Element
Ato
mic
Ra
diu
s (
pic
om
ete
r)
Li Be B C N O FNe
What trend(s) do
you notice?
Atomic size DECREASES as you go across the Periodic TableA
tom
ic size IN
CR
EA
ES
ES
as y
ou
go
dow
n th
e P
erio
dic T
ab
le
Atomic Size
Key Point #1: Atomic size increases as you go down the periodic table and decreases as you go left to right across the periodic table.
Practice Problems
Rank the following elements in order of increasing atomic size based on location on the periodic table (smallest to biggest)
Fr, Sc, P, Pd
F, As, Tl, S
P, Pd, Sc, Fr
Fluorine, Sulfur, Arsenic, Thallium
Practice Time!
1. T or F? Atomic size decreases as you move right across the periodic table.
2. T or F? As you move down the Periodic Table, atoms get smaller.
3. Rank the following sets of elements in order of increasing atomic size (small big).
Set A: Bh, Mn, Re, Tc Set B: Sb, I, Ag, Ru Set C: Y, Ti, Sg, Ta
4. Rank the following sets of elements in order of decreasing atomic size (big small).Set A: Cl, At, I, F, Br Set B: Te, Xe, Sn, In
Set C: Rb, K, Sr, Ca
What is electronegativity?
Electronegativity is… The ability of an atom to attract electrons to itself in a chemical bond
How much an atom wants electrons
Graphing Electronegativity
Draw 2 line graphs X-axis: Element Y-axis: Electronegativity (Paulings)
Elements and their Electronegativity (1)Element Electrone
gativity (Paulings)
Hydrogen 2.20
Lithium 0.98
Sodium 0.93
Potassium
0.82
Rubidium 0.82
Cesium 0.79
Francium 0.70
Element Electronegativity
(Paulings)
Lithium 0.98
Beryllium 1.57
Boron 2.04
Carbon 2.55
Nitrogen 3.04
Oxygen 3.44
Fluorine 3.98
Electronegativity Graph 1
0
0.5
1
1.5
2
2.5
0 1 2 3 4 5 6 7 8
Element
Ele
ctro
neg
ativ
ity
Electronegativity Graph 2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 2 4 6 8
Element
Ele
ctro
neg
ativ
ity
What trend(s) do
you notice?
Electronegativity
Key Point #2: Electronegativity decreases as you go down the periodic table and increases as you go left to right across the periodic table.
Electronegativity Trends
Practice Problems
Rank the following elements in order of increasing electronegativity based on location on the periodic table (smallest to biggest)
Mg, Sr, Be, Ra
Cl, Si, Al, S, P
Radon, Strontium, Magnesium, BerylliumAluminum, Silicon, Phosphorus, Sulfur, Chlorine
Practice Time!1. T or F? Electronegativity decreases as you
move left across the periodic table.2. T or F? As you move down the Periodic
Table, atoms get more electronegative.3. Rank the following sets of elements in order
of increasing electronegativity (small big). Set A: Bh, Mn, Re, Tc Set B: Sb, I, Ag, Ru Set C: Y, Ti, Sg, Ta
4. Rank the following sets of elements in order of decreasing electronegativity (big small).Set A: Cl, At, I, F, Br Set B: Te, Xe, Sn, In
Set C: Rb, K, Sr, Ca
How does atomic size related to electronegativity?
Key Point #3: Atomic size is indirectly related to electronegativity.
ELECTRONEGATIVITY
ATOMIC SIZE
As electronegativity increases, atomic size decreases!
Why is this relationship true? Atoms with HIGH
ELECTRONEGATIVITIES hold their electrons very close!
Sooooo, the atomic size decreasesHigh or low electronegativity?
Large or small atomic size?
Exit Question
1. Which element has atoms with the smallest size: Cl, Se, P, or F?
2. Which element has the largest electronegativity: Ag, Cu, Hg, or Zn?
3. As electronegativity increases, atomic size….?