Embed Size (px)
Citation preview
Drill – 11/19Drill – 11/19
What is meant by “periodic trend”?What is meant by “periodic trend”?
Periodic TrendsPeriodic Trends
Nuclear ChargeNuclear Charge
Nuclear charge-the charge in the nucleus Nuclear charge-the charge in the nucleus or the number of protonsor the number of protons
Across – increasesAcross – increases
Down – increasesDown – increases
Valence ElectronsValence Electrons
The electrons in the outermost energy The electrons in the outermost energy level (s and p orbitals only!)level (s and p orbitals only!)
Across – increaseAcross – increase
Na Mg Al Si … Ar Na Mg Al Si … Ar
3s3s11 3s 3s22 3s 3s223p3p11 3s 3s223p3p22 …3s …3s223p3p66
11 2 3 4 ... 8 2 3 4 ... 8
Valence ElectronsValence Electrons
The electrons in the outer most energy The electrons in the outer most energy level (s and p orbitals only!)level (s and p orbitals only!)
Down – stays the same. This is why Down – stays the same. This is why there are trends in reactivity for families there are trends in reactivity for families
Be Mg Ca SrBe Mg Ca Sr
2s2s22 3s 3s2 2 4s4s22 5s 5s22
2 2 2 2 2 2 2 2
Atomic MassAtomic Mass
Weighted average (based on mass and Weighted average (based on mass and percent abundance of each naturally percent abundance of each naturally occurring isotope)occurring isotope)
Across – increasesAcross – increases
Down – increasesDown – increasesRemember there are some exceptions to this – Remember there are some exceptions to this – like Te and Ilike Te and I
Shielding EffectShielding Effect
The shielding effect is The shielding effect is the reduction of the reduction of attractive force attractive force between the nucleus between the nucleus (+) and its outer (+) and its outer electrons (-) due to electrons (-) due to the blocking affect of the blocking affect of the inner electronsthe inner electrons
NucleusNucleus
Shielding electronsShielding electrons
Valence electrons ‘shielded’ by inner electronsValence electrons ‘shielded’ by inner electrons
Shielding EffectShielding Effect
Across – stays the Across – stays the samesame
Electrons are added Electrons are added in the Valence shell in the Valence shell and the shielding and the shielding electrons remain the electrons remain the samesame
0
1
2
3
Na Mg Al Si P S Cl
EnergyLevels
Shielding EffectShielding Effect
Down – increasesDown – increases
Another layer of Another layer of electrons is added electrons is added and the shielding and the shielding between the valence between the valence shell and the nucleus shell and the nucleus increasesincreases
0
1
2
3
4
5
6
7
F Cl Br I At
EnergyLevels
Atomic RadiusAtomic Radius
One half the One half the distance from distance from center to center center to center of like atomsof like atoms
1/2
Atomic RadiusAtomic Radius
Across – decreasesAcross – decreases
As the number of p+ As the number of p+ in the nucleus and e- in the nucleus and e- in the valence shell in the valence shell increases, the increases, the nucleus exerts a nucleus exerts a greater pull on all of greater pull on all of the electronsthe electrons
0
20
40
60
80
100
120
140
160
180
200
Na Al P Cl
Radius
Atomic RadiusAtomic Radius
Down – increasesDown – increases
A new energy level is A new energy level is added increasing the added increasing the size of the atomssize of the atoms
0
20
40
60
80
100
120
140
160
180
F Cl Br I At
Radius
Ionization energyIonization energy
The amount of energy The amount of energy needed to remove an needed to remove an electronelectron
11stst Ionization Energy – Ionization Energy – energy needed to energy needed to remove the 1remove the 1stst e- from e- from an atoman atom
+ Ionization+ Ionization EnergyEnergy
++ + e-
Ionization EnergyIonization Energy
Across – increasesAcross – increases
e- are more strongly e- are more strongly attracted to nucleus, attracted to nucleus, increasing the energy increasing the energy necessary to remove necessary to remove an e-an e-
0
200
400
600
800
1000
1200
1400
1600
1800
Na Mg Al Si P S Cl Ar
Ionization Energy
Ionization EnergyIonization Energy
Down – DecreasesDown – Decreases
e- are further from the e- are further from the nucleus. Less energy nucleus. Less energy is needed to remove is needed to remove an electron.an electron.
0
100
200
300
400
500
600
700
800
900
1000
Be Mg Ca Sr Ba
Ionization Energy
Ionic RadiusIonic RadiusRadius of an ion -- the size of an ion is Radius of an ion -- the size of an ion is different than the size of the atom it came different than the size of the atom it came from.from.
If an atom loses an e- then it will have a If an atom loses an e- then it will have a pos. charge and is called a CATION.pos. charge and is called a CATION.
If an atom gains an e- then it will have a If an atom gains an e- then it will have a neg. charge and is called an ANION.neg. charge and is called an ANION.
Ionic RadiusIonic RadiusCations will be Cations will be smallersmaller than the original than the original atom. This is due to a stronger nuclear atom. This is due to a stronger nuclear pull.pull.
Anions will be Anions will be largerlarger than the original than the original atom. The additional e- goes into the atom. The additional e- goes into the same energy level and the e- will repel same energy level and the e- will repel each other and spread out.each other and spread out.
ElectronegativityElectronegativity
The tendency for an atom to attract The tendency for an atom to attract electrons in a bond.electrons in a bond.
ElectronegativityElectronegativity
Across – IncreasesAcross – Increases
Stronger nuclei have Stronger nuclei have greater nuclear pull greater nuclear pull for e-.for e-.
0
0.5
1
1.5
2
2.5
3
3.5
Na Mg Al Si P S Cl
Electronegativity
ElectronegativityElectronegativity
Down – DecreasesDown – Decreases
Larger atoms have Larger atoms have less pull on e-.less pull on e-.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
F Cl Br I At
Electronegativity
Electron AffinityElectron Affinity
The energy change when an electron is The energy change when an electron is added to a neutral atom to form a negative added to a neutral atom to form a negative ionion
Higher e- affinity = easier to add an e- = Higher e- affinity = easier to add an e- = stronger nucleusstronger nucleus
Trends Across the Periodic TableTrends Across the Periodic TableShielding Effect Stays the SameShielding Effect Stays the SameAtomic Radius decreasesAtomic Radius decreasesIonization Energy IncreasesIonization Energy IncreasesElectronegativity IncreasesElectronegativity IncreasesElectron Affinity IncreasesElectron Affinity Increases
PERIODIC TABLE OF THE ELEMENTS1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 181
H1.008
2
He4.003
3
Li6.941
4
Be9.012
5
B10.81
6
C12.01
7
N14.01
8
O16.00
9
F19.00
10
Ne20.18
11
Na22.99
12
Mg24.31
13
Al26.98
14
Si28.09
15
P30.97
16
S32.07
17
Cl35.45
18
Ar39.95
19
K39.10
20
Ca40.08
21
Sc44.96
22
Ti47.87
23
V50.94
24
Cr52.00
25
Mn54.94
26
Fe55.85
27
Co58.93
28
Ni58.69
29
Cu63.55
30
Zn65.39
31
Ga69.72
32
Ge72.61
33
As74.92
34
Se78.96
35
Br79.90
36
Kr83.80
37
Rb85.47
38
Sr87.62
39
Y88.91
40
Zr91.22
41
Nb92.91
42
Mo95.94
43
Tc[98.9]
44
Ru101.1
45
Rh102.9
46
Pd106.4
47
Ag107.9
48
Cd112.4
49
In114.8
50
Sn118.7
51
Sb121.8
52
Te127.6
53
I126.9
54
Xe131.3
55
Cs132.9
56
Ba137.3
57-70*
71
Lu175.0
72
Hf178.5
73
Ta180.9
74
W183.8
75
Re186.2
76
Os190.2
77
Ir192.2
78
Pt195.1
79
Au197.0
80
Hg200.6
81
Tl204.4
82
Pb207.2
83
Bi209.0
84
Po[209]
85
At[210]
86
Rn[222]
87
Fr[223]
88
Ra[226]
89-102**
103
Lr[262]
104
Rf[261]
105
Db[262]
106
Sg[263]
107
Bh[264]
108
Hs[265]
109
Mt[268]
110
Uun[269]
111
Uuu[272]
112
Uub[277]
114
Uuq[289]
116
Uuh[289]
118
Uuo[293]
*lanthanoids 57
La138.9
58
Ce140.0
59
Pr140.9
60
Nd144.2
61
Pm[145]
62
Sm150.4
63
Eu152.0
64
Gd157.3
65
Tb158.9
66
Dy162.5
67
Ho164.9
68
Er167.3
69
Tm168.9
70
Yb173.0
**actinoids 89
Ac[227]
90
Th232.0
91
Pa231.0
92
U238.0
93
Np[237]
94
Pu[244]
95
Am[243]
96
Cm[247]
97
Bk[247]
98
Cf[251]
99
Es[252]
100
Fm[257]
101
Md[258]
102
No[259]
Version Date 29 February 2000
Trends Down the Periodic TableTrends Down the Periodic TableShielding Effect Shielding Effect IncreasesIncreasesAtomic Radius Atomic Radius IncreasesIncreasesIonization Energy Ionization Energy DecreasesDecreasesElectronegativity Electronegativity DecreasesDecreasesElectron Affinity Electron Affinity DecreasesDecreases
PERIODIC TABLE OF THE ELEMENTS1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 181
H1.008
2
He4.003
3
Li6.941
4
Be9.012
5
B10.81
6
C12.01
7
N14.01
8
O16.00
9
F19.00
10
Ne20.18
11
Na22.99
12
Mg24.31
13
Al26.98
14
Si28.09
15
P30.97
16
S32.07
17
Cl35.45
18
Ar39.95
19
K39.10
20
Ca40.08
21
Sc44.96
22
Ti47.87
23
V50.94
24
Cr52.00
25
Mn54.94
26
Fe55.85
27
Co58.93
28
Ni58.69
29
Cu63.55
30
Zn65.39
31
Ga69.72
32
Ge72.61
33
As74.92
34
Se78.96
35
Br79.90
36
Kr83.80
37
Rb85.47
38
Sr87.62
39
Y88.91
40
Zr91.22
41
Nb92.91
42
Mo95.94
43
Tc[98.9]
44
Ru101.1
45
Rh102.9
46
Pd106.4
47
Ag107.9
48
Cd112.4
49
In114.8
50
Sn118.7
51
Sb121.8
52
Te127.6
53
I126.9
54
Xe131.3
55
Cs132.9
56
Ba137.3
57-70*
71
Lu175.0
72
Hf178.5
73
Ta180.9
74
W183.8
75
Re186.2
76
Os190.2
77
Ir192.2
78
Pt195.1
79
Au197.0
80
Hg200.6
81
Tl204.4
82
Pb207.2
83
Bi209.0
84
Po[209]
85
At[210]
86
Rn[222]
87
Fr[223]
88
Ra[226]
89-102**
103
Lr[262]
104
Rf[261]
105
Db[262]
106
Sg[263]
107
Bh[264]
108
Hs[265]
109
Mt[268]
110
Uun[269]
111
Uuu[272]
112
Uub[277]
114
Uuq[289]
116
Uuh[289]
118
Uuo[293]
*lanthanoids 57
La138.9
58
Ce140.0
59
Pr140.9
60
Nd144.2
61
Pm[145]
62
Sm150.4
63
Eu152.0
64
Gd157.3
65
Tb158.9
66
Dy162.5
67
Ho164.9
68
Er167.3
69
Tm168.9
70
Yb173.0
**actinoids 89
Ac[227]
90
Th232.0
91
Pa231.0
92
U238.0
93
Np[237]
94
Pu[244]
95
Am[243]
96
Cm[247]
97
Bk[247]
98
Cf[251]
99
Es[252]
100
Fm[257]
101
Md[258]
102
No[259]
Version Date 29 February 2000
