Principles of Chemistry Introduction to the Principles of Chemistry Rena Abbasova Baku Higher Oil School, September 2013

Text book: Chemistry, 2 nd Edition by Blackman, Bottle, Schmid, Mocerino and Wille Reference to book pages on notes e.g. [T p15-20]

Modes of Learning  Lectures  Tutorials  Webtests  Workshops  Private study

Lectures New concepts, new facts Make your own notes - Focus on the main points! Review your notes asap after each lectures Your attendance is obligatory!

Tutorials Individual attention to the students More interactive and specific than a book or a lecture Help develop your understanding of the subject, not test it Your attendance is required!

Webtests Relate to the lecture material Available via the University virtual learning environment – VISION Formative not summative (This semester ONLY) Possibility of repeated attempts (as often as you wish)

Workshops they help develop your understanding of the subject, not test it! Problems will be given out in advance Self study before workshop is obligatory! Your attendance is required!

Private study (Self-study) You must supplement your timetabled time with private study! Revising and Supplementing lectures notes Reading the textbook Researching and answering tutorial questions

To succeed in exam you need to be strongly motivated: Read the textbook Attend lectures, tutorials and workshops and be active Research and answer tutorial questions Work before and at the workshops Use webtests Spare no effort to private study

Schedule of course Week LectureTutorialWebtestWokshopPrivate study 1Intro, 1-32 ≥ 6 hrs (L1-4) ≥ 6 hrs ≥ 6 hrs (L6-9)1 (L6-9)≥ 6 hrs (L10-13)2(L10-13)≥ 6 hrs (L14-17)3(L14-17)≥ 6 hrs (L18-21)4(L18-21)≥ 6 hrs ≥ 6 hrs (L22-25)5 (L22-25)≥ 6 hrs (L26-29)6 (L26-29)≥ 6 hrs (L30-33)7(L30-33)≥ 6 hrs 1236, 3729 (L34-37)8(L34-37)≥ 6 hrs

Principles of Chemistry The course covers topics of General, Inorganic and Organic Chemistry: 1. Stoichiometry and Reactions 2. Atomic Structure 3. Molecular Shape and Chemical Bonding 4. Main-Group Chemistry 5. Introductory Organic Chemistry

What is chemistry? the study of matter and energy and the interactions between them. It tends to focus on the properties of substances and the interactions between different types of matter, particularly reactions that involve electrons. the study of substances and their transformation

The building block of matter Atom

Chemical Elements Each elements is made of the same kind of atoms Currently, there are about 118 elements discovered; some are found in nature and some are man-made. Elements carry the names and symbols.

Periodic Table [Textbook p13-15]

Electronic configuration of atom Chemistry is mostly the study of electron interactions between atoms and molecules. Understanding the behavior of the electrons in an atom is an important part of understanding chemical reactions. The properties of an atom's electron configuration are described by four quantum numbers: n, l, m, and s. Orbitals that have the same principal quantum number, n, are part of the same electron shell. Orbitals that have the same n and l, they are in the same subshell.

Principal quantum number n. n is an integer (n = 1, 2, 3, 4,etc…), n defines the size and the energy of the orbital (an electron shell). Azimutal quantum number l, can be any number between 0 and (n-1). (l = 0, 1, 2, …,(n-1)), l defines the shape of the orbital (electron sub-shells). Magnetic quantum number m l. can be any number between –l and +l. (m = -l, -(l-1), …0, …, (l-1), l. m l defines the orientation of the orbital. Spin quantum number m s can be + ½ or -½. ms describes the electron spin. Electrons also have the further property of spin that can occur in two ways. Notation: m s = +½ is noted ↑; m s = -½ is noted ↓. Quantum numbers

The Building-Up Principle

THE PERIODICITY OF ATOMIC PROPERTIES

Potential energy curves - Morse curves When H – H distance = 74 pm, Repulsion = Attraction  strongest bond  optimal overlap  lowest energy CHEMICAL BOND

Intramplecular Intermolecular The type of bond depends on the difference in electronegativity and distribution of electron density CHEMICAL BOND Bond typeCovalentIonicMetallic Types of atoms involved Mainly non-metalsSome non-metals and some metals Metals only Nature of bonds between atoms Sharing of electronsTransfer of electrons Delocalisation of electrons

THEORIES OF CHEMICAL BONDING Valence bond theory: It explained the formation of covalent bonds between atoms, which is supposed to be formed due to overlapping of atomic orbitals. Molecular orbital theory : The atomic orbitals of bonding atoms combine with each other by giving rise to molecular orbitals. MO-LCAO

Molecular Shape Valence Shell Electron Pair Repulsion Theory VSEPR A model in chemistry used to predict the shape of individual molecules based upon the extent of electron-pair electrostatic repulsion. It is also named Gillespie- Nyholm theory after its two main developers. The geometry around an atom is described by the general formula: AX m E n, where X is a bonded atom, E is a lone pair and (m+n) is the number of objects (sometimes called the steric number, SN) around the central atom A. AX 4 TetrahedralAX 3 E (Trigonal) Pyramidal

VSEPR Molecular Shapes

e-pairsNotationName of VSEPR shapeExamples 2AX 2 LinearHgCl 2, ZnI 2, CS 2, CO 2 3AX 3 Trigonal planarBF 3, GaI 3 AX 2 ENon-linear (Bent)SO 2, SnCl 2 4AX 4 TetrahedralCCl 4, CH 4, BF 4 - AX 3 E(Trigonal) PyramidalNH 3, OH 3 - AX 2 E 2 Non-Linear (Bent)H 2 O, SeCl 2 5AX 5 Trigonal bipyramidalPCl 5, PF 5 AX 4 EDistorted tetrahedral (see-sawed) TeCl 4, SF 4 AX 3 E 2 T-ShapedClF 3, BrF 3 AX 2 E 3 LinearI 3 -, ICl 2 - 6AX 6 OctahedralSF 6, PF 6 - AX 5 ESquare PyramidalIF 5, BrF 5 AX 4 E 2 Square PlanarICl 4 -, BrF 4 - Summary of VSEPR Molecular Shapes

Law of Mass Conservation The law of mass conservation implies that atoms can neither be created nor destroyed during a chemical reaction, although they may be rearranged, and/or their state of matter may change. The direct implication of the law of mass conservation is that chemical reaction equations must be balanced. Types of Chemical reaction in Aqueous Solution Precipitation/dissolution Acid/base reactions (Brǿnsted-Lowry (B-L) ) Redox reactions Stoichiometry

Oxidation-Reduction Reactions

Oxidation-Reduction Reactions in Aqueous Solutions REDOX reactions can be balanced in one of two ways: HCl + MnO 2  Cl 2 + MnCl 2 + H 2 O (1)The OXIDATION-STATE METHOD|| The oxidation number method. (2) The HALF-EQUATION METHOD || The half reaction method. (ion- electron method) MnO H + +2 е -  Mn H 2 O Cl - -2 е -  Cl ________________________________________  equation MnO H + +2 Cl - +2 е -  Mn 2+ + H 2 O+ Cl 2 +2 е - 4 HCl + MnO 2 = Cl 2 + MnCl H 2 O

Chemistry of the Elements of the Main Group

Environmental Impact of Main Group Compounds ACID RAIN OZONE DEPLETION GREENHOUSE EFFECT

What is acid rain? Acid rain typically has a pH from 4.0 to 5.4 What are the causes of acid rain? SO 2, SO 3, No x What are the effects of acid rain? Damages buildings, statues Corrodes marble and metals Causes human respiratory diseases Increases the acidity of soil Induces the release of aluminum ions from soil particles Acidifies lakes What can we do to solve the problems brought by acid rain?

OZONE DEPLETION Ozone layer in the stratosphere protects the Earth’s surface from UV light Ozone depletion refers to a lowered concentration of ozone in the upper atmosphere “Holes” are formed  More UV radiation is reaching the Earth’s surface What are the causes of ozone depletion? Presence of chlorofluorocarbons (CFCs) Presence of oxides of nitrogen Presence of halogens Presence of bromine

The 3 major greenhouse gases are: water vapour (36 to 70%), carbon dioxide (9 to 26%), methane (4 to 9%). Other contributors include nitrous oxide, ozone and CFCs. Most of the incoming solar radiation is in the visible part of the spectrum Most visible light passes through the atmosphere without being absorbed The earth radiates heat back out towards space when warmed up Much of the radiation does not escape into space Most is trapped by certain gases in the atmosphere, carbon dioxide and particular water vapour GREENHOUSE EFFECT Greenhouse effect is an excess of heat created due to the high concentrations of some gases

What is global warming? Global warming refers to the gradual increase in the average temperature in the atmosphere Increase in concentration of greenhouse gases in the atmosphere The heat loss from the Earth to the Space is slowed down An enhancement of the greenhouse effect leads to global warming Greenhouse gases include carbon dioxide, chlorofluorocarbons, methane, nitrous oxides, ozone, water vapour, etc

Thank you for attention!