chapter 8 the periodic table. what is the periodic table good for?
TRANSCRIPT
Chapter 8The Periodic Table
What is the Periodic Table good for?
The Periodic Table Symbols and names Protons, electrons, &
neutrons Atomic mass Size of atoms & ions Strength of ions
(electronegativity) Electron configuration
Atomic SizeHow is atomic size determined?
The electron cloud doesn’t have a definite edge.
Atomic Size
Atomic Radius = half the distance between two nuclei of a diatomic molecule.
}Radius
Trends in Atomic Size Influenced by two factors:1. Energy Level
- Higher energy level is further away.
2. Charge on nucleus- More charge pulls electrons
in closer.
Group trends
Increasing number of energy levels
HLi
Na
K
Rb
Periodic Trends As you go across a period the
radius gets smaller. Same energy level. More nuclear charge.
Na Mg Al Si P S Cl Ar
Ionic Size Cations formed by losing electrons.
Metals form cations. Cations of representative elements have noble gas configuration.
Ionic size Anions form by gaining electrons.
Nonmetals form anions. Anions of representative elements have noble gas configuration.
Group trends
Increasing number of energy levels
Li+1
Na+1
K+1
Rb+1
Cs+1
Periodic Trends
Energy level changes between anions and cations.
Li+1
Be+2
B+3
C+4
N-3 O-2 F-1
Electronegativity
The tendency for an atom to attract electrons to itself when it is in a compound
Group Trend The further down a group, the farther the electron from the nucleus
More willing to share. Lower electronegativity.
Periodic TrendMetals are at the left end
•Metals lose electrons•Low electronegativity
At the right end are the nonmetals.•Nonmetals gain electrons•High electronegativity.
Electron ConfigurationAtomic Orbitals fill up in a
regular pattern.
The outside orbital electron configuration repeats.
Therefore, the properties of atoms repeat.
1s1
1s22s1
1s22s22p63s1
1s22s22p63s23p64s1
1s22s22p63s23p64s23d104p65s1
1s22s22p63s23p64s23d104p65s24d10
5p66s1
1s22s22p63s23p64s23d104p65s24d10
5p66s24f145d106p67s1
H1
Li3
Na11
K19
Rb37
Cs55
Fr87
He2
Ne10
Ar18
Kr36
Xe54
Rn86
1s2
1s22s22p6
1s22s22p63s23p6
1s22s22p63s23p64s23d104p6
1s22s22p63s23p64s23d104p65s24d105p6
1s22s22p63s23p64s23d104p65s24d10
5p66s24f145d106p6
Alkali metals all end in s1
Alkaline earth metals all end in s2
Helium included is S - block
s2s1 S- block
Transition Metals -d block
d1 d2 d3s1
d5 d5 d6 d7 d8s1
d10 d10
The P-block
p1 p2 p3 p4 p5 p6
F - block inner transition elements
f1 f5f2 f3 f4
f6 f7 f8 f9 f10 f11 f12 f14
f13
Each row (or period) is the energy level for s and p orbitals.
1
2
3
4
5
6
7
D orbitals fill up after previous energy level
1
2
3
4
5
6
7
3d
f orbitals start filling at 4f
1
2
3
4
5
6
7 4f
5f
Writing Electron Configurations the Easy
Way
Electron Configurations Repeat
As you move across a period, the outermost energy level is filled
This is the basis for writing shorthand electron configurations.
The Shorthand
Aluminum 1s22s22p63s23p1
Ne is 1s22s22p6
so Al is [Ne] 3s23p1
The Shorthand Again
Sn- 50 electrons
The noble gas before it is Kr
[ Kr ]
Takes care of 36
Next 5s2
5s2
Then 4d10
4d10Finally 5p2
5p2