SPARKS

CH301

ELECTRON CONFIGURATION, TRENDS, and BONDING

UNIT 2 Day 6

Important Information

Assigned: - LM18 and HW 11 - Study these topics in fundamentals in eBook: Ionic and Covalent Bonding Nomenclature Know name/symbols for elements through #92 - Nomenclature quiz Monday. Non-graded LM that may be useful for study: - Laude LM Lectures 5, 6, 7 - NGM10 – covalent nomenclature - NGLM11 ionic nomenclature - NGLM07 Periodic Table Basics

INDIVIDUAL QUIZ: NO TALKING!

The trend on the periodic table is that atomic radii: a) Increases as you move from L to R across b) Decreases as you move from R to L across c) Increases as you move from T to B down d) Increases as you move from B to T up e) Both b and c

INDIVIDUAL QUIZ: NO TALKING!

The trend on the periodic table is that ionization energy increases as you move a) from L to R across and from T to B down. b) from R to L across and from T to B down. c) from L to R across and from B to T up. d) from R to L across and from B to T up. e) From L to R across and does not change as

you move from T to B.

What are we going to learn today?

−Electron Configuration, Trends, and Bonding

• Relate the valence shell electron configuration to

ionization energy

• Relate the valence shell electron configuration to

bonding

• Understand the similarities and differences between

ionic and covalent bonding

• Recognize and name compounds based on elemental

composition

IONIZATION ENERGY

7

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Atomic Number

Ionization

Energy

(kJ/mol)

H

He

Li

Be

B

C

N

O

F

Ne

Na

Mg

Al

Si P

S

Cl

Ar

K

Ca

Based on this trend in ionization energies this element is A. argon B. carbon C. magnesium D. sulfur

Trends provide useful information! Why can Sr be dangerous?

• What biologically important element would you expect it to be chemically similar to?

Where are the electrons in Ne? 1s22s22p6 very stable gas Z=10

Where are the electrons in Na? [Ne]3s1 not so stable metal Z=11

Where are the electrons in K? [Ar]4s1 not so stable metal Z=19 Easier or harder to ionize than Na?

ELECTRON LEAVES.. WHERE DOES IT GO?

Metals tend to give up electrons to nonmetals, in each case the valence is “satisfied” Sometimes is complicated… eg in the sodium in water demo Sometimes is more obvious… 2Na(s) + Cl2(g) 2NaCl(s) Sometimes they are already gone!

Formation of Ionic Compound – Downhill in Energy

IELi = 520 kJ/mol

Electron Affinity of fluorine

oE change when a gas phase atom gains an electron.

o= EAF = -328 kJ/mol

oNote that net energy change is still positive – less stable! Why does LiF form?

The structure of lithium fluoride

Ionic Compound… downhill in energy…..

Ionic Compounds…

Not a discrete pair of ions…it is a whole collection

Coulomb’s Law Lattice energy depends on Coulomb’s Law and the crystal structure (the way the ions are packed together). Assuming the same crystal structure, which do you think would have the larger lattice energy: a)NaF b)NaBr?

POLL: CLICKER QUESTION

Ionic Radius

What is your expectation of the lattice energy for MgO – large or small?

Which would have the larger lattice energy?

A. CaS

B. NaCl

POLL: CLICKER QUESTION

Polyatomic Ions

Calcium Carbonate Ca2+ CO3

2- Know the names and formulas for all the common polyatomic ions. See the Data & Tables under “more” on the eBook

Naming Ionic Compounds

Choose the formula that corresponds to: sodium oxide

a)NaO

b)NaO2

c)Na2O

d)Na2O2

POLL: CLICKER QUESTION

Naming Ionic Compounds

You need to be able to name common ionic compounds and with elemental ions and polyatomic ions. WEBSITE – FUNDAMENTALS – DO THE WORKSHEETS

What have we learned?

NUCLEAR CHARGE FELT BY VALENCE ELECTRONS IS SHIELDED BY THE CORE ELECTRONS ATOMS BEHAVE IN CERTAIN PREDICTABLE WAYS WHICH CAN BE CORRELATED TO THE ELECTRON CONFIGURATIONS IONIC BONDS TEND TO FORM BETWEEN METALS AND NONMETALS COVALENT BONDS TEND TO FORM BETWEEN NONMETALS AND NONMETALS NAMING COMPOUNDS IS IMPORTANT AND NECESSARY

Learning Outcomes

Identify metals and non-metals and predict types of compounds (ionic/covalent) Between different elements Relate coulombs law and lattice energy Name basic binary ionic compounds including polyatomic ions