UNIT VIIIAtoms and the Periodic Table

Lesson#2

Electronic Structure/configuration

VIII.1 THE STRUCTURE OF THE ATOM

F. The Electronic Structure of the Atom

Energy Level Diagrams:

ENERGY LEVEL: is a specific amount of energy which an electron in an atom can possess (n)

QUANTUM: the energy difference between two particular energy levels

VIII.1 THE STRUCTURE OF THE ATOM

VIII.1 THE STRUCTURE OF THE ATOM

ORBITAL: is the actual region of space occupied by an electron in a particular energy level

SHELL: is the set of ALL orbitals having the same n-value

SUBSHELL: is a set of orbitals of the same type

 

VIII.1 THE STRUCTURE OF THE ATOM

Four Different Types of Oribitals:1. s-type: 1 s-orbital2. p-type: 3 p-orbitals3. d-type: 5 d-orbitals4. f-type: 7 f-orbitals

* each orbital contains only 2 electrons

Shapes of orbitals

The Five 3d orbitals chime d-orbitals more

The 7f orbitals

VIII.1 THE STRUCTURE OF THE ATOM

Electron Configurations:

Definition: a description of which orbitals in an atom contain electrons and how many electrons are in each orbital

VIII.1 THE STRUCTURE OF THE ATOM

TWO RULES when adding electrons to orbitals:1.As atomic number increases, electrons are added to orbitals with lower energy first

2.A maximum of 2 electrons can be placed in each orbital

ENERGY LEVELS (N)

n=1 contains only s

n=2 contains s, p

n=3 contains s,p,d

n=4 contains s,p,d,f

n> 4 also contain s,p,d,f

Remember…

Four Different Types of Oribitals:1. s-type: 1 s-orbital max of 2. p-type: 3 p-orbitals max of3. d-type: 5 d-orbitals max of4. f-type: 7 f-orbitals max of

* each orbital contains only 2 electrons

How to write electronic configuration

H: 1 electron, goes to lowest energy level, n=1

 N: 7 electrons

VIII.1 THE STRUCTURE OF THE ATOM

VIII.1 THE STRUCTURE OF THE ATOM

* Use the periodic table to help…

VIII.1 THE STRUCTURE OF THE ATOM

* Use the periodic table to help…

VIII.1 THE STRUCTURE OF THE ATOM

Core Notation:

CORE of an ATOM – is the set of electrons with the configuration of the nearest noble gas (He, Ne, Ar, Kr etc...)

OUTER electrons – consist of all electrons outside of the core

*core electrons usually don’t take part in chemical reactions

VIII.1 THE STRUCTURE OF THE ATOM

Ex: Predict the electron configuration of the following ions, using CORE NOTATION 

Rb:

Ge:

Ni:

Fe:

*Ar:

VIII.1 THE STRUCTURE OF THE ATOM

If the d-shell is one electron short of being filled or half-filled, one electron from the s-shell comes over to fill it…makes it more stable

Cr ([Ar] 4s2 3d4) d4 – not stable 

Cr ([Ar] 4s13d5) d5 – much more stable

Cu([Ar] 4s2 3d9) d9 – not stableCu([Ar] 4s13d10) d10 – stable

VIII.1 THE STRUCTURE OF THE ATOM

Electron Configuration for IONS:

Negative Ions: ADD electrons to the last unfilled subshell 

Positive Ions: REMOVE electrons from outermost shell (largest n-value) first, if electrons are in p and s, remove from p first!

VIII.1 THE STRUCTURE OF THE ATOM

Electron Configuration for IONS:

Ca2+:

Se2-:

Core Vs Valence Electrons

Core Electrons usually don’t take part in chemical reactions

Valence Electrons: electrons which can take part in chemical reactions *all electrons in an atom except those in CORE or filled d and f shells

Core Vs Valence Electrons

Ex: How many valence electrons do the following contain?

B 

Li

Is there a trend??? You betcha!

Number of column/group = number of valence electrons!

Cs

Core Vs Valence Electrons

Try: How many valence electrons are in?

Number of column/group = number of valence electrons!

Po

Sb+3

O2-

Br-

HOMEWORK

Electronic structure of atom

Hebden p. 155 # 26 a,c,d,f,g,k p. 156 #27 ( for any 4 of your choice) p. 157 # 28 choose 2 positive ions and 2

negative ions. p. 158 #29 (a i )

EXTENSION...

NOT TESTABLE !!!

The quarks are permanently confined by forces coming from the exchange of "gluons." He and others later constructed …quantum chromodynamics," which seems to account for all the nuclear particles and their strong interactions." ...

In 1969, Professor Murray Gell-Mann received the Nobel Prize in physics for his work on the theory of elementary particles …he found that all of those particles, including the neutron and proton, are composed of fundamental building blocks that he named "quarks."

Quantum Chromodynamics

Protons and Neutrons are composed of

smaller particles called quarks

A proton consists of two “up” and one “down” quark.

“Flavors” of quarks

Different combinations of quarks produce different particles

Quarks are held together by “gluons”

Will it ever end?