CHEM 120: Introduction to Inorganic Chemistry

Instructor: Upali Siriwardane (Ph.D., Ohio State University)

CTH 311, Tele: 257-4941, e-mail: upali@chem.latech.edu

Office hours: 10:00 to 12:00 Tu & Th ; 8:00-9:00 and 11:00-12:00 M,W,& F

Chapters Covered and Test dates

Tests will be given in regular class periods from 9:30-10:45 a.m. on the following days:

September 22,     2004 (Test 1): Chapters 1 & 2

October 6,           2004(Test 2): Chapters 3, & 4

October 20,         2004 (Test 3): Chapter 5 & 6

November 3,        2004 (Test 4): Chapter 7 & 8

November 15,      2004 (Test 5): Chapter 9 & 10

November 17,      2004 MAKE-UP: Comprehensive test (Covers all chapters

Grading:

[( Test 1 + Test 2 + Test3 + Test4 + Test5)] x.70 + [ Homework + quiz average] x 0.30 = Final Average

                                            5

Chapter 3: Elements, atoms, ions, and the periodic table

3.1 The periodic law and the periodic table

Early periodic tables

1817: Döbreiner's triads – 3 elements w/ regularly varying properties: S Se Te

1865: Newlands – "law of octaves", about 55 elements

Early tables were based on mass number (A) or “combining weight”

Modern periodic table

1869: Mendeleev and Meyer – "properties of the elements are a periodic function of their atomic weights;" 63-element table.

1913: Moseley – X-ray emission spectra vary with atomic number (Z)

Modern periodic law:

"______:"

______: horizontal rows (seven in all); properties of elements in period show no similarity.

Note that the lanthanides (period six) and the actinides (period seven) are at the bottom of the table

"_______: (families)"

_______: (families) are the columns of elements. The elements in the groups have similar chemical properties and predictable trends in physical properties.

Groups also have labels. Group A elements are the _____________ elements and the Group B are the ___________ elements.

Note that there is another way of labeling the groups with nos. 1-18.

"We give some groups some..."

We give some groups some names

IA are the

IIA the

VIIA the

VIIIA the

Metals and nonmetals

_______ are shiny, good conductors of heat and electricity, malleable, ductile, and form cations (positive ions, loss of electrons) during chemical change.

___________ are not shiny. They are poor conductors, brittle. They frequently form anions (negative, gain of electrons) in chemical changes.

"Metalloids have some characteristics of..."

Metalloids have some characteristics of both metals and nonmetals. They are B, Si, Ge, As, Sb, Te, Po, At.

How to tell metals from nonmetals: Be B Al Si Ge As Sb Te Po At

"Some elements are gases at..."

Some elements are gases at room temperature: hydrogen, nitrogen, oxygen, fluorine, chlorine, VIIIA’s; two are liquids--bromine and mercury (Hg); the rest are solids.

More info from periodic table

26 atomic number Fe chemical symbol 55.85 atomic mass

"Question 3.2 plus a..."

Question 3.2 plus a few others:

the symbol of the noble gas in period 3

the lightest element in Group IVA

the only metalloid in Group IIIA

the element whose atoms contain 18 protons

the element in period 5, Group VIIA

Give the name, atomic number and atomic mass for Mg

"For each of the elements..."

For each of the elements Ca, K, Cu, Zn, Br and Kr

Answer:

    which are metals?

     which are representative metals?

     which tend to form positive ions

     which are inert or noble gases

Electron arrangement and the periodic table

Electron arrangement: tells us how the electrons are located in various orbitals in an atom--will explain a lot about bonding

Quantum mechanical atom

Heisenberg uncerrtainty princple and deBroglie wave-particle duality concept lead to concept of electrons in orbitals, not orbits. Waves are spread out in space and this concept contradicts the Bohr model where electrons had very specific locations.

"Schrödinger combined wave and particle..."

Schrödinger combined wave and particle mechanics (mass) to describe an e- in an atom.

The solns to the eqn are called wave functions.

The wave function completely describes (mathematically) the behavior of the e- in an atom.

"A wave function"

A wave function describes an orbital of a certain energy. Not all energies are allowed (energy of e- is quantized).

An _______ is a region in space where there is a large probability of finding an electron.

Each atomic orbital has a characteristic energy and shape.

The concept of quantization is a mathematical consequence of solving the Schroedinger equation, not an assumption.

Principal energy levels (shells)

The principal energy levels are designated by the quantum no. n.

Allowed values of n:

Each e- in an atom can be found only in certain allowed principal energy levels (shells) (designated by the q. no. n)

"Larger the value of n"

Larger the value of n, the more likely we are to find the e- at a larger distance from the nucleus with a larger energy (not as stable).

Each energy level is subdivided into ________. The number of sublevels in an energy level is equal to the

"n = 1"

n = 1

n = 2

n=4

No. of electrons in a principal energy level

Each principal energy level can hold at most _________ electrons

So n= 1

n= 2

n = 5

Sublevels

Principal energy levels are subdivided into sublevels.

Sublevels have the designation s, p, d, f and in terms of energy s<p<d<f.

The value of n tells us how many sublevels are in a principal energy level.

"So for n = 1..."

So for n = 1 there is one sublevel __. The 1 gives us the principal energy level and the s tells us the type of orbital that is found in that sublevel.

For n =2 we have __and __ sublevels making up that energy level.

For n= 3 we have

For n =4 we have

For n=5 we have

We don’t worry about any type of orbital (sublevel) beyond f.

Orbitals

An orbital is a region in space where there is a large probability of finding an electron.

Each orbital can hold at most _ electrons. So an orbital can be

Types of orbitals are designated by the s, p, d, f letters.

"The s sublevel is made..."

The s sublevel is made up of _ orbital shaped like a sphere and can hold at most _ electrons.

The p sublevel is made up of ______orbitals. Since each orbital can hold a maximum of 2 electrons, the set of p sublevels can hold a total of _____ electrons.

"The d sublevel is made..."

The d sublevel is made up of ______ orbitals. Since each orbital can hold a maximum of 2 electrons, the set of d sublevels can hold a total of ___ electrons.

The f sublevel is made up of ______ orbitals. Since each orbital can hold a maximum of 2 electrons, the set of f sublevels can hold a total of __ electrons.

Slide 29

Slide 30

Slide 31

Electron spin

Each orbital can hold at most two electrons. Electrons also have spin (turning on an axis) and have magnetic properties (deflected in magnetic field). Electrons in the same orbital must have opposite spins. If they have opposite spins the electrons are said to be paired.

What to do with all this info?

Rules for writing electron configuration:

1. The no. of electrons in neutral atom = atomic no. (no. of protons)

2. Fill the lowest energy sublevel completely, then the next lowest, etc.

3. No more than two electrons can be placed in a single orbital. The electrons have opposite spins in the same orbital. (2 electrons in s, 6 in p, 10 in d, 14 in f)

"4."

4. For n=1,

For n =2

For n=3,

For n=4,

Remember the order of filling as follows:

Slide 35

How to remember the energy order

1s

2s 2p

3s 3p 3d

4s 4p 4d 4f

5s 5p 5d 5f 5g

6s 6p 6d 6f 6g 6h

7s 7p 7d 7f

"Let’s do some electron configurations"

Let’s do some electron configurations

Abbreviated electron configuration

₂He   1s²

₁₀Ne   1s²2s²2p⁶

₁₈Ar    1s²2s²2p⁶3s²3p⁶

₃₆Kr    1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶

These configurations are for ground state configurations--lowest energy.

Valence electrons

Valence electrons are the electrons located in the _________ orbitals and are the ones involved in forming chemical bonds. The valence electrons have the largest _ value for the A elements.

For representative elements the number of valence electrons in an atom =

"Don’t worry about inner core..."

Don’t worry about inner core of electrons (smaller n) since these are filled levels and don’t enter into bond formation ( for A groups)

Valence electron configuration for A groups

Group IA

Group IIA

Group IIIA

Group IVA

Group VA

Group VIA

Group VIIA

Group VIIIA

Where do you get the numerical value for the n for the valence electrons?

You find the _______ number!!!

Can you use this information to make electron configuration easier?

"Valence electron configuration for:"

Valence electron configuration for:

P

Bi

Sr

Te

I

Cs

The octet rule

It has been noted that extra stability occurs when an atom or ion has 8 electrons in the outermost energy level (2 or 0 for the first period).

"Group IA"

Group IA    ns¹

Lose

Group IIA   ns²

Loses

Group IIIA ns²np¹

Loses

Group IVA ns²np²

Group VA    ns²np³

Gains

Group VIA   ns²np⁴

Gains

Group VIIA ns²np⁵

Gains

Group VIIIA ns²np⁶

"Group IA"

Group IA

Group IIA

Group IIIA

Group VA

Group VIA

Groupr VIIA

Names of ions: for cations--name of element plus ion

For anions: replace the last syllables of the element name by --ide + ion.

Transition metal cations

No simple rules as for A groups

Cu⁺, Cu²⁺

Fe²⁺, Fe³⁺

Au⁺, Au³⁺

"H^-"

H^-

H⁺

Li⁺

Be²⁺

B³⁺

N^3-

O^2-

F^-

What’s the ion formed by

P

Ba

S

N

I

Cs

Slide 50

Isoelectronic

Atoms or ions

F^- [He] 2s²2p⁶

O^2- [He] 2s²2p⁶

Name a cation isoelectronic with O^2-

Question

Which of the following pairs of atoms and ions are isoelectronic?

Cl^-, Ar

Na⁺, Ne

Mg²⁺, Na⁺

Li⁺, Ne

O^2-, F^-

"Which of the following groups..."

Which of the following groups are isoelectronic with each other?

Na⁺, Mg²⁺, Ne

Cl^-, F^-, Ar

Na⁺, Mg²⁺, Al³⁺, N^3-, O^2-, F^-, Ne

3.4: Trends in the periodic table

Think of atom as sphere whose radius is determined by the location of the e’s furthest from the nucleus.

So atomic radius (size) determined by:

1. Larger value of n for atom in a group, the larger the atom size. Size _________ from top to bottom in group.

Size across a period

As go across a period (n stays the same), the no. of protons in the nucleus increases. The e’s are very spread out and each electron feels the pull of the increasing +charge of the nucleus uninfluenced by the other electrons and size __________ as go from left to right across a period.

Slide 56

"Group"

Group size increases

Period size decreases (with some exceptions)

Slide 58

"Arrange each of the lists..."

Arrange each of the lists according to increasing atomic size:

Al, S, P, Cl, Si

In, Ga, Al, B, Tl

Sr, Ca, Ba, Mg, Be

P, N, Sb, Bi, As

Na, K, Mg

Ion size

Same charge, in group, size __creases

Size of parent to cation:

Parent   cation

Size of parent to anion:

Parent   anion

Fe²⁺   Fe³⁺

"Which is smaller?"

Which is smaller?

Cl or Cl-

Na or Na⁺

O^2- or S^2-

Mg²⁺ or Al³⁺

Au⁺ or Au³⁺

Slide 62

"Note for isoelctronic series:"

Note for isoelctronic series:

Na⁺, Mg²⁺, Al³⁺, N^3-, O^2-, F^-,

N^3-> O^2-> F^-> Na⁺> Mg²⁺> Al³⁺

Most positive ion the smallest, most negative the largest

Ionization energy

Minimum energy required to remove an electron from a ground-state, gaseous atom

Energy always positive (requires energy)

Measures how tightly the e^- is held in atom (think size also)

Energy associated with this reaction:

Trends in ionization energy

Top to bottom in group: 1st I.E. __creases. Why?

Across a period, 1st I.E. __creases (irregularly) Why? Note that noble gases have the largest I.E. in a given period; the halogens the next highest; the alkali metals the lowest, etc.

Slide 66

Slide 67

Arrange in order of increasing I.E.

N, O, F

Li, K, Cs

Cl, Br, I

Electron affinity

Electron affinity is energy change when an e^- adds to a gas-phase, ground-state atom

Energy associated with this reaction:

Positive EA means that energy is released, e- addition is favorable and anion is stable!

First EA’s mostly positive, a few negative

Trends in electron affinities

Decrease down a group and increase across a period in general but there are not clear cut trends as with atomic size and I.E.

Nonmetals are more likely to accept e-s than metals. VIIA’s like to accept e-s the most.

Slide 71


	Instructor: Upali Siriwardane (Ph.D., Ohio State University)
	CTH 311, Tele: 257-4941, e-mail: upali@chem.latech.edu
	Office hours: 10:00 to 12:00 Tu & Th ; 8:00-9:00 and 11:00-12:00 M,W,& F


	Tests will be given in regular class periods from 9:30-10:45 a.m. on the following days:
	September 22, 2004 (Test 1): Chapters 1 & 2
	October 6, 2004(Test 2): Chapters 3, & 4
	October 20, 2004 (Test 3): Chapter 5 & 6
	November 3, 2004 (Test 4): Chapter 7 & 8
	November 15, 2004 (Test 5): Chapter 9 & 10
	November 17, 2004 MAKE-UP: Comprehensive test (Covers all chapters
	Grading:
	[( Test 1 + Test 2 + Test3 + Test4 + Test5)] x.70 + [ Homework + quiz average] x 0.30 = Final Average
	5


	1817: Döbreiner's triads – 3 elements w/ regularly varying properties: S Se Te

	1865: Newlands – "law of octaves", about 55 elements

	Early tables were based on mass number (A) or “combining weight”


	1869: Mendeleev and Meyer – "properties of the elements are a periodic function of their atomic weights;" 63-element table.

	1913: Moseley – X-ray emission spectra vary with atomic number (Z)

	Modern periodic law:


	______: horizontal rows (seven in all); properties of elements in period show no similarity.
	Note that the lanthanides (period six) and the actinides (period seven) are at the bottom of the table


	_______: (families) are the columns of elements. The elements in the groups have similar chemical properties and predictable trends in physical properties.

	Groups also have labels. Group A elements are the _____________ elements and the Group B are the ___________ elements.
	Note that there is another way of labeling the groups with nos. 1-18.


	We give some groups some names
	IA are the
	IIA the
	VIIA the
	VIIIA the


	_______ are shiny, good conductors of heat and electricity, malleable, ductile, and form cations (positive ions, loss of electrons) during chemical change.
	___________ are not shiny. They are poor conductors, brittle. They frequently form anions (negative, gain of electrons) in chemical changes.


	Metalloids have some characteristics of both metals and nonmetals. They are B, Si, Ge, As, Sb, Te, Po, At.

	How to tell metals from nonmetals: Be B Al Si Ge As Sb Te Po At


	Some elements are gases at room temperature: hydrogen, nitrogen, oxygen, fluorine, chlorine, VIIIA’s; two are liquids--bromine and mercury (Hg); the rest are solids.


	Question 3.2 plus a few others:
	the symbol of the noble gas in period 3
	the lightest element in Group IVA
	the only metalloid in Group IIIA
	the element whose atoms contain 18 protons
	the element in period 5, Group VIIA
	Give the name, atomic number and atomic mass for Mg


	For each of the elements Ca, K, Cu, Zn, Br and Kr
	Answer:
	which are metals?
	which are representative metals?
	which tend to form positive ions
	which are inert or noble gases


	Electron arrangement: tells us how the electrons are located in various orbitals in an atom--will explain a lot about bonding


	Heisenberg uncerrtainty princple and deBroglie wave-particle duality concept lead to concept of electrons in orbitals, not orbits. Waves are spread out in space and this concept contradicts the Bohr model where electrons had very specific locations.


	Schrödinger combined wave and particle mechanics (mass) to describe an e- in an atom.
	The solns to the eqn are called wave functions.
	The wave function completely describes (mathematically) the behavior of the e- in an atom.


	A wave function describes an orbital of a certain energy. Not all energies are allowed (energy of e- is quantized).
	An _______ is a region in space where there is a large probability of finding an electron.
	Each atomic orbital has a characteristic energy and shape.
	The concept of quantization is a mathematical consequence of solving the Schroedinger equation, not an assumption.


	The principal energy levels are designated by the quantum no. n.
	Allowed values of n:

	Each e- in an atom can be found only in certain allowed principal energy levels (shells) (designated by the q. no. n)


	Larger the value of n, the more likely we are to find the e- at a larger distance from the nucleus with a larger energy (not as stable).
	Each energy level is subdivided into ________. The number of sublevels in an energy level is equal to the


	Each principal energy level can hold at most _________ electrons
	So n= 1

	n= 2
	n = 5


	Principal energy levels are subdivided into sublevels.
	Sublevels have the designation s, p, d, f and in terms of energy s<p<d<f.
	The value of n tells us how many sublevels are in a principal energy level.


	So for n = 1 there is one sublevel __. The 1 gives us the principal energy level and the s tells us the type of orbital that is found in that sublevel.
	For n =2 we have __and __ sublevels making up that energy level.
	For n= 3 we have
	For n =4 we have
	For n=5 we have
	We don’t worry about any type of orbital (sublevel) beyond f.


	An orbital is a region in space where there is a large probability of finding an electron.
	Each orbital can hold at most _ electrons. So an orbital can be

	Types of orbitals are designated by the s, p, d, f letters.


	The s sublevel is made up of _ orbital shaped like a sphere and can hold at most _ electrons.

	The p sublevel is made up of ______orbitals. Since each orbital can hold a maximum of 2 electrons, the set of p sublevels can hold a total of _____ electrons.


	The d sublevel is made up of ______ orbitals. Since each orbital can hold a maximum of 2 electrons, the set of d sublevels can hold a total of ___ electrons.

	The f sublevel is made up of ______ orbitals. Since each orbital can hold a maximum of 2 electrons, the set of f sublevels can hold a total of __ electrons.


	Each orbital can hold at most two electrons. Electrons also have spin (turning on an axis) and have magnetic properties (deflected in magnetic field). Electrons in the same orbital must have opposite spins. If they have opposite spins the electrons are said to be paired.


	Rules for writing electron configuration:
	1. The no. of electrons in neutral atom = atomic no. (no. of protons)
	2. Fill the lowest energy sublevel completely, then the next lowest, etc.
	3. No more than two electrons can be placed in a single orbital. The electrons have opposite spins in the same orbital. (2 electrons in s, 6 in p, 10 in d, 14 in f)


	4. For n=1,
	For n =2
	For n=3,
	For n=4,


	Remember the order of filling as follows:


	1s
	2s 2p
	3s 3p 3d
	4s 4p 4d 4f
	5s 5p 5d 5f 5g
	6s 6p 6d 6f 6g 6h
	7s 7p 7d 7f


	₂He 1s²
	₁₀Ne 1s²2s²2p⁶
	₁₈Ar 1s²2s²2p⁶3s²3p⁶
	₃₆Kr 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶
	These configurations are for ground state configurations--lowest energy.


	Valence electrons are the electrons located in the _________ orbitals and are the ones involved in forming chemical bonds. The valence electrons have the largest _ value for the A elements.
	For representative elements the number of valence electrons in an atom =