الرئيسيةكيمياء المجموعات : كيم٢٢٢

222 Chem: Main Group Chemistry

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Instructor

Dr. Nouf H. Alotaibi

Office: 5T242

Office Hours: Sunday, Tuesday and Thursday 11-12 or by appointment.

Email: nhalotaibi@ksu.edu.sa

Email correspondence must be from your @ksu.edu.sa account.

Please include 222 Chem in the subject line

Lecture and Tutorial Information

Lectures

3 h/week, STTh, 9-10.

Class room 038/ 01/05

Tutorial

1 h/week, S. 12:00- 1:00.

Class room 038/ 01/05

Evaluation

• Tests: There will be two exams with 20 marks each and total 40 mark.

First midterm test on 20/6/1438 corresponding to 19/3/2017.Second midterm test on 19/7/1438 corresponding to 16/4/2017.• Tutorial: 20 mark,

• Final Exam: 40 mark.

Course Reference

The list here is merely suggestive and possibly representative. There are many other good

books and course materials as well.

1. W. Henders: Main Group Chemistry, RSC Publishin, 2000.

2. J E Huheey, E. A. Keiter, R. L. Keiter and O. K. Medhi; Inorganic Chemistry: Principles

of Structure and reactivity, Pearson Education, 2006.

3. P. W. Atkins, T. Overton, J. Rourke, M. Weller and F. Armstrong; Shriver & Atkins:

Inorganic Chemistry, Fourth Edition, Oxford University Press, 2006.

4. F. A. Cotton, G. Wilkinson, C. A. Murillo and M. Bochmann; Advanced Inorganic

Chemistry, Sixth Edition, Wiley, 1999.

5. N. N. Greenwood and E. A. Earnshaw, Chemistry of the Elements, Second Edition,

Elsevier 1997.

6. الرئيسيةالمجموعاتلكيمياءالنظريةاالسس , العبيكانمكتبة , منشيمحمود , 1994.

7. عمادة شئون المكتبات . جامعة الملك سعود, محمد علي خليفة الصالح.كيمياء المجموعات الرئيسية

1990جامعة الملك سعود، (الرياض)

Introduction:

Main group chemistry?

Main Group elements??

Periodic Table?

The table is a visual

representation of the periodic law

which states that certain properties

of elements repeat periodically

when arranged by atomic number.

The table arranges elements into

vertical columns (Groups) and

horizontal rows (Periods) to display

these commonalities.

اوال المجموعات الرئيسية هي العناصر الواقعة في المجموعات

(A) بالرمزبالجدول الدوري للعناصر ويرمز لها الرئيسة

هذه المجموعات في يسار و يمين الجدول الدوري وتسمى وتقع

. التمثيليةبالعناصر ايضا

ثانيا كيمياء هذه المجموعات يقصد به دراسة هذه العناصر من

( مركباتها-استخالصها-تفاعالتها )ناحية خواصها الكيميائية

ويدخل ضمنها الخواص الفيزيائية و تدرج خواصها

The history of the periodic table:

Chemical elements such as gold, silver and copper were known .

About 330 B.C Aristotle proposed that everything is made up of a mixture

of one or more of four "roots" .

the understanding of the nature of matter.

Plato, the four elements were;

Earth, Water, Air and Fire.

Aristotle's and Plato's ideas did nothing to

advance

The history of the periodic table:

Lavoisier(1789) الفوازييه

The first modern chemical text book.

It contained a list of elements, or substances that could not be

broken down further, which included oxygen, nitrogen,

hydrogen, phosphorus, mercury, zinc, and sulfur.

Prouts Hypothesis (1815- 1816).

H2

المادةهو

لتكويناالولية

العناصرجميع

The history of the periodic table:

The law of triads- dobereiner (1817).

According to Dobereiner, elements can be

arranged in increasing order of their atomic

mass.

He arranged all the known elements in

groups of three each.

These groups are called triads.

In each triad, elements are arranged

in increasing order of their atomic mass.

The atomic mass of the middle element is

equal to the average atomic mass of both the

terminal elements. These triads are also termed

as Dobereiner triads.

The history of the periodic table:

Octaves Law of Newlands (1864).

Elements arranged in order of their relative atomic masses.

any given element will exhibit analogous behaviour to the eighth element following it in

the table.

Newland assumed only 56 elements existed so far. Later new elements were discovered

which did not fit into octaves table.

Newland adjusted few elements in a same slot though their properties were quite different.

E.g. Cobalt and nickel are in the same slot and these are placed in the same column as

fluorine, chlorine and bromine which have very different properties than these elements.

Who Is The Father of the

Periodic Table ?

The history of the periodic table:

(1869-1870) ?

Meyer: (1864-1870)

Half of the known elements (28).

demonstrated periodic valence changes as

a function of atomic weight.

Meyer constructed an extended table

which he gave to a colleague for evaluation

(1868).

Meyer's table appeared (1870).

The German Lothar Meyer or the

Russian Dmitri Mendeleev.

Both chemists produced similar results at the same time working independently

of one another.

Mendeleev: (1869)

63 known elements.

Element's symbol, atomic weight and its

characteristic chemical and physical

properties.

Mendeleev arranged the elements in a

table ordered by atomic weight (molar mass).

Mendeleev's table became available (1869).

Nobel Prize (1906).

Mendeleev: (1869)

1. The elements, if arranged according to their atomic weights, exhibit an apparent

periodicity of properties.

2. Elements which are similar as regards to their chemical properties have atomic weights

which are either of nearly the same value (e.g., Pt, Ir, Os) or which increase regularly

(e.g., K, Rb, Cs).

3. The arrangement of the elements, or of groups of elements in the order of their atomic

weights, corresponds to their so-called valencies, as well as, to some extent, to their

distinctive chemical properties; as is apparent among other series in that of Li, Be, Ba, C,

N, O, and Sn.

4. The elements which are the most widely diffused have small atomic weights.

5. The magnitude of the atomic weight determines the character of the element.

6. We must expect the discovery of many yet unknown elements–for example, elements

analogous to aluminium and silicon–whose atomic weight would be between 65 and 75.

7. The atomic weight of an element may sometimes be amended by a knowledge of those of

its contiguous elements. However Moseley later explained the position of these elements

without revising the atomic weight values .

8. Certain characteristic properties of elements can be foretold from their atomic weights.

Elements or properties of elements depend periodically on

their atomic weights.

Mendeleev (1869)

This version of Mendeleev's periodic table from 1891. It is lacking the noble gases.https://upload.wikimedia.org/wikipedia/commons/5/5f/Mendeleev_Table_5th_II.jpg

Scientific benefits of Mendeleev's table:

Mendeleev predicted the discovery of other elements and left space for these

new elements, namely eka-silicon (germanium), eka-aluminium (gallium), and

eka-boron (scandium). Thus, there was no disturbance in the periodic table.

He pointed out that some of the then current atomic weights were incorrect.

He provided for variance from atomic weight order.

Shortcomings of Mendeleev's table:

His table did not include any of the noble gases, which were discovered later.

These were added by Sir William Ramsay as Group 0, without any disturbance to

the basic concept of the periodic table.

There was no place for the isotopes of the various elements, which were

discovered later.

Discovery of the Noble Gases:

In 1895 Lord Rayleigh ريليه

New gaseous element named argon proved to be chemically inert.

This element did not fit any of the known periodic groups.

In 1898, William Ramsey

Argon be placed into the periodic table between chlorine and potassium in a

family with helium.

Argon's atomic weight was greater than that of potassium?!!.

This group was termed the "zero" group (zero valency of the elements).

Ramsey accurately predicted the future discovery and properties neon.

Atomic Structure and the Periodic Table:

Ernest Rutherford (1911)

Studied the scattering of alpha particles by heavy atom nuclei, determinate the nuclear

charge. شحنة النواة

Demonstrated the nuclear charge on a nucleus was proportional to the atomic weight of

the element.

A. van den Broek (1911)

The atomic weight of an element was approximately equal to the charge on an atom.

This charge ( later called the atomic number) could be used to number the elements within

the periodic table.

Henry Moseley (1913) موزلي

Measured the wavelengths of the x-ray spectral lines of a number of elements which

showed that the ordering of the wavelengths of the x-ray emissions of the elements coincided

with the ordering of the elements by atomic number.

With the discovery of isotopes of the elements, it became clear that atomic weight was not

the significant player in the periodic law as Mendeleev, Meyers and others had proposed, but

rather, the properties of the elements varied periodically with atomic number.

Atomic number vs. Atomic weight:

The atomic number of an atom is simply

the number of protons in its nucleus.

The atomic weight is given in most cases

by the mass number of the atom, equal to

the total number of protons and neutrons

combined.

The Modern Periodic Table:

The last major changes to the periodic table resulted

from Glenn Seaborg's work in the middle of the

20th Century.

Discovered plutonium (Pu) in 1940;

Discovered all the transuranic ( اليورانيومبعدما )

elements from 94 to 102;

Reconfigured the periodic table by placing the

actinide series below the lanthanide series.

Nobel Prize in chemistry (1951).

Element 106 has been named seaborgium (Sg).

2011: added elements 114 and 116.

International Union of Pure and Applied Chemistry (IUPAC) on 13 December 2015

announced a researchers from Russia and US reached a sufficient evidence of the

discovery of new elements, which are 113, 115, 117, 118.

8 June 2016: IUPAC is naming the four new additions to the table:

nihonium, moscovium, tennessine, and oganesson.

نيهونيوم موسكوفيوم تينيسين اوغانيسون

How Many Elements

Can Be Found in the

periodic table?

How Many Elements

Can Be Found

Naturally?

118 elements

98 elements

Elements 93-98 (neptunium, plutonium, americium, curium, berkelium, and californium)

were all first artificially synthesized and isolated in the Berkeley Radiation Laboratory of

the University of California.

The Modern Periodic Table:

Periodic table contains; 7 horizontal rows (periodes), and 18 vertical columns

(groups).

Four sections: the Right, the Left, and the middle, and the end of the table.

Section left: the main group elements (A): two groups (A1, A2) and called (the

alkali metals).

Section right: the rest of the group (A); (A3 to A7),

defined as non-metals, and semi-metals, and the rest of other metals, and Nobel

gases, or inert and halogens.

Middle section: group (B), includes 30 component, called the transitional elements.

The final section consists of two series of elements :

First series: called lanthanides, includes 14 elements, and begin the element cerium.

Second Series: called actinides, includes 14 element, and begin the element thorium

s-block p-block

d-block

f-block

The Modern Periodic Table- Classification of elements:

Videos

https://www.youtube.com/watch?v=t_f8bB1kf6M&feature=youtu.be

https://youtu.be/t_f8bB1kf6M

Transcripthttps://www.khanacademy.org/science/chemistry/periodic-table/copy-of-periodic-table-of-elements/v/periodic-table-introduction

Atomic Electron Configurations

يقصد بـ ترتيب اإللكتروني للعناصر

هو الكيفية التي تتوزع فيها اإللكترونات في مدارات الذرة

ويحكم توزيع اإللكترونات في مدارات الذرة عدد من القواعد

،قاعدة أوف باو

،قاعدة هوند

قاعدة االستبعاد لباولي

قاعدة افباو: اوال

مبدأ البناء التصاعدى

تدخل اإللكترونات في

مستويات الطاقة الفرعية ذات

الطاقة المخفضة أوال ثم تمأل

األعلى منها بعد ذلك

مالحظة

طاقة المدار تزداد بزيادة عدد

الكم

n الرئيسيوهو يمثل طاقة المدار

ومدى بعده عن النواة

مبدأ باولي لالستبعاد: ثانيا

ينص هذا المبدأ على أنه ال يمكن أن

تتساوى األعداد الكمية األربعة ألي

إلكترونين في ذرة واحدة

،فعلى سبيل المثال

ال يمكن إللكترونين في ذرة واحدة

أن يكون لهم ذات أعداد الكم

األربعة؛ فإذا كان

nو ،ℓو ،mℓ

متشابهين بين إلكترونين أو أكثر،

فإن

ms

يجب أن يكون مختلفا

بمعنى أن كل واحد منهم يدور

معاكس لآلخرباتجاه

قاعدة هوند

ال يحدث ازدواج بين إلكترونين في "

مستوي فرعي معين إال بعد أن تشغل

لتقليل التنافر -" مداراته فرادى أوال

.بينهما

مثال

مدار P

مدارات متساوية في الطاقة هي3يحوي

Px ,Py, Pz

،كل منهم يستوعب إلكترونين

أو أقل فأنه 3فإذا كانت عدد اإللكترونات

يتم توزيعها فرادى على المدارات الثالث

وإذا زاد عن الثالثة فيتم البدء في دمج

.اإلكترونات

Effective Nuclear Charge

Zeff = Z − S

[19] : Ar, 4s1 Group number

Period number Block

To find the position (group & period) of element in Periodic

table and identify its properties. (Except Transition elements)

Periodic Trends

• Arises from the Periodic patterns in ELECTRON CONFIGURATIONS.

• Elements in the same GROUP have the same number of VALENCE electrons

• VALENCE electrons = electrons in the outermost orbital

• Chemical and physical properties of element depend on the

Atomic Electron Configurations ( valence electrons)

• Observed trends in

– Sizes of atoms and ions.

– Ionization energy.

– Electron affinity.

Sizes of Atoms

The bonding atomic radius

is defined as one-half of the

distance between covalently

bonded nuclei.

Bonding atomic radius tends to… …decrease from left to right across a row due to increasing Zeff.

…increase from top to bottom of a column due to increasing value of n

Sizes of Atoms

For the same shell value

(n) the penetrating power of

an electron follows this trend

in subshells:

s>p>d>f

Electronic Configuration for Elements in Period 2

Element # of protonsElectron

Configuration

Lithium (Li) 3 1s22s1

Beryllium (Be) 4 1s22s2

Boron (B) 5 1s22s22p1

Carbon (C) 6 1s22s22p2

Nitrogen (N) 7 1s22s22p3

Oxygen (O) 8 1s22s22p4

Fluorine (F) 9 1s22s22p5

As we move ACROSS the

periodic table, the nuclear

charge increases while the

number of energy levels

occupied by electrons remains

the same.

The number of core electrons

remains constant.

Which of the following ATOMS is largest

N , O , F?

S or O?

Na or Cl?

Na or K?

----- Same period, N

----- Same group, S

----- Same period, Na

----- Same group, K

Sizes of IonsIonic size depends upon:

– Nuclear charge.

– Number of electrons.

– Orbitals in which

electrons reside.

CATIONS lose

electrons and are

SMALLER THAN

THE PARENT

ION.

ANIONS add

electrons and are

LARGER THAN

THE PARENT

ION.

Sizes of Ions

• Cations are smaller

than their parent

atoms.

– The outermost

electron is

removed and

repulsions are

reduced.

– Zeff increase

Sizes of Ions

• Anions are larger than their

parent atoms.

– Electrons are added and

repulsions are increased.

– Zeff decrease

Sizes of Ions

• Ions increase in size as you go

down a column.

– Due to increasing value of

n.

Sizes of Ions

• In an isoelectronic series, ions have the same number of electrons.

• Ionic size decreases with an increasing nuclear charge.

ISOelectronic series

A group of ions all containing the same number of electrons

How many electrons do

O2- ; F- ; Na+ ; Mg2+ and Al3+ have ?

10

-- Increasing nuclear charge

O2- > F- > Na+ > Mg2+ > Al3+

--- Decreasing ionic radius

K+ and Ca2+ (18)

Ca2+ and Sc3+ (18)

S2- and Ar (18)

Fe2+ and Co3+ (24)

Which of the following is largest ?

• Na or K ?

• Na or Mg ?

• S2– or O2– ?

• S2–, S, or O2– ?

• K+, Cl–, Ca2+ , or S2– ?

• O2– , F- , Na+ , Mg 2+ , or Al 3+

Arrange the ions K+, Cl–, Ca2+ and S2– in order of DECREASING size.

These form an isoelectronic series of ions

Size decreases as the nuclear charge of the ion increases.

The atomic numbers of the ions are S (16), Cl (17), K (19), and Ca (20)

K+, Cl–, Ca2+ and S2– all have 18

-- Increasing nuclear charge

--- Decreasing ionic radius

S2– > Cl–> K+ > Ca2+

Arrange O 2- , F - , Na + , Mg 2+ , Al 3+ according to size

As nuclear charge increases in an isoelectronic series the ions become smaller

all have 10

O 2- > F - Na + Mg 2+ Al 3+

Ionization Energy

• Amount of energy required to remove an electron from the ground state of a

gaseous atom or ion.

– First ionization energy is that energy required to remove first electron.

– Second ionization energy is that energy required to remove second

electron, etc.

El ------- El+ + e-

Example:

Na ------- Na+ + e-

Ionization Energy

• It requires more energy to remove each successive electron.

• When all valence electrons have been removed, the ionization energy takes

a quantum leap.

Periodic Trends in Ionization Energies

Ionization energy decreases going down a group

Ionization energy generally increases across a period.

Trends in First Ionization Energies

• going down a column,

less energy to remove

the first electron.

For atoms in the same

group,

Zeff is the same, but

the valence electrons

are farther from the

nucleus.

Trends in First Ionization Energies

Generally, it gets harder to

remove an electron going

across.

– As you go from left

to to right, Zeff

increases.

Trends in First Ionization Energies

On a smaller scale, there are two jags in each line. Why?

n-=2,

4Be:1s22s2

5B:1s22s22p1

7N:1s22s22p3

8O:1s22s22p4

Metalloide