Do Now: 1) Take out and turn in the homework (reading summary)2) Put these terms in order of most general to most specific Orbital, Sublevel, PEL, Spin3) Write the quantum atom electron configuration AND box diagram for calcium

Do now Review (pre quiz!)

Quiz time!

Adele says:“Put everything away and no

talking. Cheating isn’t cool.”

Kernel vs. Valence and Periodic Trends

The Kernel, Valence Electrons & Lewis Dot Diagrams A very powerful tool for showing

how different elements bond together

Lewis (Electron) Dot Diagrams developed by a chemist named

G.N. Lewis.

The Kernel, Valence Electrons & Lewis Dot Diagrams Many times in chemical bonding: only the electrons on the outside or in

the highest energy level, called the VALENCE SHELL, actually become involved in bonding to form compounds.

We are going to look at the Lewis (Electron) Dot Diagrams and elements in this next section.

The Kernel, Valence Electrons & Lewis Dot Diagrams Valence Shell: Outermost energy level of an

element (highest number) Oxygen: O 2-6 the 2nd principle energy

level is the valence shell

The Kernel, Valence Electrons & Lewis Dot Diagrams Valence Electrons (VE): electrons located in

the outermost energy level These are the electrons which are the furthest

to the right in the electron configuration found on the PT

How many VE does Oxygen have? 6

The Kernel, Valence Electrons & Lewis Dot Diagrams  Valence Electrons (VE): electrons located

in the outermost energy level the 6 electrons are the valence electrons In a dot diagram, the VE are represented

by dots:   Kernel: This is the nucleus and all the other

electrons located in the inner energy levels In a dot diagram, the chemical symbol

represents the kernel: O

Sidebar: Visualizing

Kernel

Valence

The Kernel, Valence Electrons & Lewis Dot Diagrams The valence shell always contains only 4 orbitals. These orbitals are represented by the four sides around

the symbol. The top side represents s orbital which has less energy

than the other three p orbitals. The other three p orbitals have the same amount of

energy. Represented by the other 3 sides. First 2 electrons are always placed first in this top

orbital. Going around clockwise, one electron is placed on each

remaining side until you need to pair the electrons up.

4 sides of the “Kernel”Lower Energy than p – fill w/

2e- 1st

O(Ovals are just drawn to show

the orbitals)

O

S

P

P

P

Place 1 e- in eachP 1st before pairing b/c same Energy

Period 2 Dot DiagramsSymbol Li Be B CElectron Configur

ation Dot

Diagram

Period 2 Dot DiagramsSymbol N O F NeElectron Configur

ation Dot

Diagram

Guided Practice: look for a pattern!Symbol Electron Configuration (Circle the

Valence Electrons (VE) Number of VE

Dot Diagram

SSeNaK

Guided Practice: look for a pattern!Symbol Electron Configuration (Circle the

Valence Electrons (VE) Number of VE

Dot Diagram

SiGeClBr

Guided Practice: look for a pattern!Symbol Electron Configuration (Circle the

Valence Electrons (VE) Number of VE

Dot Diagram

ArKr

What is the pattern in Dot diagrams?

PERIODIC TABLE: PROPERTIES OF ELEMENTS and TRENDS One of the most useful tools to a chemist

is the Periodic Table. There are several important trends or

patterns. Electronegativity is an important tool for

predicting the type of bonding that will be present.

We will look at these trends and then use them to help explain and predict bonding later in the course.

Electronegativity Attraction for electrons in a bond found on Reference Table S based on Fluorine (F), 4.0For Metals (left side of PT) it tends to be LOW

because inner electrons shield the attraction of the nucleus for other electrons in the valence shell

For Nonmetals (right side of PT) it tends to be high because nuclear charge is large compared to small size and attracts the electrons closer

Electonegativity Trend Across a period (L->Rt) Increases Down a Group Decreases

Ionization Energy: Energy needed to remove the outermost

electron found on Reference Table S For Metals (left side of PT) it tends to be LOW For Nonmetals (right side of PT) it tends to be

HIGH

Ionization Energy: Across a period (L->Rt) Increases Down a Group Decreases Why? Metals are larger and electrons are attracted

less so more easily removed than smaller nonmetal atoms

Down a group, more principle energy levels so outer electrons are further from the attraction of nucleus, more easily removed

How do the trends for electronegativity and ionization energy compare?

Atomic Radii: Size of the neutral atom found on Reference Table S

radii Increases as you go down a group (add) on the PT, because there are more energy levels present

radii Decreases as you go across the Periodic Table

Left Right because increased nuclear charge attracts energy levels closer

Ionic Radii: Size of the atom after it gains or loses

electrons Metals form __(+)__ ions (cations) by

losing electrons & get smaller because losing

the valence electrons leaves the energy level empty

Ionic Radii of Metals: Bohr Model of

Neutral Atom   Bohr model of Li

ion of Li (Li+1)

Ionic Radii of Nonmetals Nonmetals form __(-)__ ions

(anions) by _Gaining____ electrons & get Bigger because

the added electron(s) expand the atom because there are more electrons than protons

Ionic Radii of Nonmetals Bohr Model of Neutral Bohr Model

an ion of Atom of F F (F-1)

Do now: FINISH YOUR ATOM BOOKS (should

be able to do the dot diagrams and what not now)

Finish the homework