Transcript Kelter chapter 2 part 2

Chapter 2 – Part 2
Orbitals and Periodic Table
Atoms & The Periodic Table
• Discovery of the Sub-Atomic Particles
– contributed by several famous scientist
• Ernest Rutherford (1911)
– nucleus is smaller an the atom and is positively
charged, electrons surround nucleus
• Henry Moseley (1914)
– relationship between elements and atomic
number, later related to protons
Atoms & The Periodic Table
• Neils Bohr (1913)
– student of Rutherford
– envision electrons moving around the nucleus
• Studied the line emissions from Hydrogen
Energy Level Diagram
Energy
Excited
States
Energy
Ground State
Emitted
Light
Atoms & The Periodic Table
• Neils Bohr (1913)
– student of Rutherford
– envision electrons moving around the nucleus
• Studied the line emissions from Hydrogen
• Bohr’s Model
– electrons move in around the nucleus and
electrons are in different energy levels.
Electrons & The Periodic Table
• Atoms have many Energy Levels (Shells)
– energy levels are number: 1, 2, 3, etc
• Energy Levels are populated with electrons
– 2n2 electrons in energy level
• Electrons in an Energy Level have a
discrete energy
Electrons & The Periodic Table
• Energy Levels Farther from are Nucleus
Higher in Energy
• Energy Levels have Orbitals
– each orbital can only have two electrons
– orbit vs. orbitals
• Orbitals are representations of Electrons in
Energy Level
Electrons & The Periodic Table
• Electrons fill Orbitals in an Organized Way
– electron configuration
• Electron Configuration determines Periodic
Table
Electrons & The Periodic Table
• Inner Shell Electrons - Core Electrons
• Outer Shell Electrons - Valence Electrons
– determine the bonding between atoms
– 최외곽 전자수가 같으면 같은 족
Parts of an Atom
What Makes an Element?
• X = Atomic Symbol
• Z = atomic number
A
X
Z
Y
– # of protons
• A = mass number
– # of proton & neutrons
• Y = net charge
– # of electrons
Atoms
•
•
15N
51Cr3+
• p+(7), e- (7), n (8)
• p+ (24), e- (21), n (27)
•
239Pu
• p+ (94), e- (94), n (145)
•
56Fe2+
• p+(26), e- (24), n (50)
Exploring the Periodic Table
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
V
Cr
Rb
Sr
Y
Zr
Nb
Mo Tc
Cs
Ba
Lu
Hf
Ta
W
Fr
Ra
Lr
Rf
Ha
La
Ce
Ac
Th
Mn Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Sg
Ns
Hs
Mt
110
111
112
Pr
Nd
Pm Sm Eu
Gd
Tb
Dy
Ho
Er
Tm Yb
Pa
U
Np
Am Cm Bk
Cf
Es
Fm Md No
Alkali Metals group
Alkaline Earth Metals
Pu
Halogens
Noble Gases
Exploring the Periodic Table
• Group 8A - Noble Gases
– inert gases (He, Ne, Ar, Kr, Xe, Rn)
– 8 electrons in outer shell - Octet 옥테트
– do not give up electrons
• Group 1A - Alkali Metals
–
–
–
–
reacts violently with water
soft metal, low melting points
1 electron in outer shell
tend to lose electron form +1 charge
Exploring the Periodic Table
• Group 7A - Halogens
– exist as diatomic molecules (F, Cl, Br, I)
– 7 electrons in outer shell
– gain 1 electron to form -1 charge
• Group 2A - Alkaline Earth Metals
– react with water, but not as violently
– 2 electrons in outer shell
– lose 2 electrons to form +2 charge
Exploring the Periodic Table
• Group 3A
– 3 electrons in outer shell
– tend to form +3 charge
– aluminum and boron are important commercially
• Group 4A
– 4 electron in outer shell
– can form +4 charge, but carbon and silicon do not like
to form charged species
– carbon is essential to all life (organic chemistry)
Exploring the Periodic Table
• Group 5A
– 5 electrons in outer shell (N, P)
– tend to gain 3 electrons to form -3 charge
– heavier atoms can form other charged species
• Group 6A
– 6 electron in outer shell (O, S)
– can gain 2 electrons to form -2 charge
– oxygen is most abundant element
Exploring the Periodic Table
• Transition Metals
–
–
–
–
Fe, Cu, Ni, Zn
high melting points (except Hg)
high density
conductive
• Inner Transition Metals
– Lanthanides & Actinides are extremely rare
– atomic numbers >92 are synthetic elements
(Look their names)
– many have radioactive isotopes