Rasdida Saeed Ayesha Hashmi Unzila Zulufqar Rabia Shafique Hina Nawaz

1. Rabia Akber Yumna Asma AnumWaqar Faiza Iqbal Naghza Fatima Community Of Molecules Thinkers: • Rasdida Saeed • Ayesha Hashmi • Unzila Zulufqar • Rabia Shafique • Hina Nawaz

2. BUILDING BLOCK Matter is made up of atoms. The structure of atoms dictate their properties. How atoms combine dictate what we see in the Compounds in nature.

3. Molecules formerly believed to be produced only by living system have been found spontaneously form in great abundance in space.

4. Atoms form community by three methods: 1. Sharing of electrons 2. Transference of electrons 3. Donation of electrons WAY OF FORMING OF COMMUNITY OF MOLECULES

5. Bonds hold atoms together. Bonding involves the valence electrons (outermost shell) electrons

6. Cl Cl Cl Cl Sharing of electrons:SINGLE COVALENT BOND Cl2 sharing of a pair of electrons and the formation of molecules

7. O O O O O O double bond (2 pairs) DOUBLE COVALENT BOND; Sharing of two electron pairs O2

8. TRIPLE COVALENT BOND; Each atom shares three electrons. N N N N N N N N triple bond (3 pairs) N2

9. O O O O O O double bond (2 pairs) N N N N N N N N triple bond (3 pairs) Atoms Share until octet is complete. H2 H2 octet complete H H H H H H Single bond( 1 pair) O2 N2

10. Sharing of electrons results in covalent Bonds H H Single covalent bond O O Double covalent bond N N Triple covalent bond

11. normal covalent bond (each atom supplies an electron) coordinate covalent bond (the pair of electrons from the same atom) H H H H H H Some more sharing examples NH3 N NH3 + H+ NH4+ NH4+ H+ N

12. How sharing occurs The two atoms will bring themselves at such a distance, that attractive forces dominate the repulsive forces.

13. Atoms hold shared electrons equally H2

14. Covalent bond between two similar atoms results in equal distribution of charge.

15. Atoms do not always play fair.Sometimes in a covalent bond they do not share equally. Cl - + H Cl H One atom pulls the shared electron pair

16. Difference in Electronegative values Unequal distribution of charges Polar covalent bond

17. Electronegativity indicates the nature of covalent bonds.

18. Formation of an ionic bond. Cl Na formation of ions electron transfer + - Na Cl NaCl Electrostatic force of attraction

19. Transferor electrons Completes octet

20. Octet complete NaCl

21. “By transference of electrons, bonded atoms are changed into ions and his type of bonding is called ionic bonding.”

22. Comparison of Bonding Types ionic covalent ions molecules molten salts conductive non- conductive valence electrons transfer of electrons sharing of electrons high mp low mp

23. IMPORTANCE OF COMMUNITY OF MOLECULES FROM COMMUNITY OF MOLECULESWE CAN OBTAIN: 1. Cosmetics lip stick, make-up kits & lip lose are all exist due to community of molecules.

24. 2. Metals Jewelry & other ornaments exist only due to community of molecules. 3. FURNITURE It includes all the interior decoration houses & buildings. Glass

25. Plastic

26. 6. Paper All kinds of paper exists due to this community 7. Medicines These are also made up of community of molecules

27. 8.Paints Paints include different kinds of community of molecules. 9. Detergents & soaps These are also produce due to communication.

28. 10. SYNTHETIC FIBERS These are also produced from one unit which is molecules community. 11. Textile Clothes are also manufacture due to community of molecules.

29. 12. Minerals Minerals consists of large community of molecules. 13. Food Different kinds of molecules make our food.

30. Human Beings; We are the most complex community of molecules. Plants. Plants are composed of molecules.

31. References: http://www.google.com http://www.ebay.com http://www.amazon.com http://www.historyofuniverse.com http://www.visionlearning.com http://www.beyondbooks.com http://www.clickatutor.com http://www.chem.ufl/chem2o4o

32. More Sources • www.google.com • www.ebay.com • www.rubber-quoite.com • www.oxforduniversity.com • www.encyclopedia.com