Nanochemistry

1. Nanochemistry FNI 1E Chemistry

2. Review of Chemistry • States of Matter • Atoms, Molecules and Ions • Subatomic particles • Periodic Table • Covalent and ionic bonding • Chemical reactions • Inter-molecular forces FNI 1E Chemistry

3. States of Matter FNI 1E Chemistry

4. Matter • Solution: A uniform mixture of two substances such that molecules are separate from each other and move around randomly. Usually these are liquids. Solutions are usually transparent. • Colloids: A mixture of much larger particles ranging from 20 nm to 100 μm. Milk and paint are colloids. • Grains: Some materials are made up of many small crystals called grains. A grain is an individual crystal of such a solid. Different grains may have the crystal lattice oriented in different directions. FNI 1E Chemistry

5. Grain Structure in Steel FNI 1E Chemistry

6. Elements, Atoms and Molecules • Atoms: All matter is made up of tiny particles called atoms. • Molecules: Sometimes two or more atoms are found bound together to form molecules. • The atoms can be categorized into about 115 different types based on the charge of the nucleus. • Elements are made up of only one type of atom. • The element carbon takes the form of graphite, diamond and buckminsterfullerene as well as others. • It is only possible to change one type of atom into another through nuclear processes such as take place in a nuclear power plant, the sun, atomic bombs or particle accelerators. • The elements do not change in ordinary chemical reactions. FNI 1E Chemistry

7. The Periodic Table FNI 1E Chemistry

8. Subatomic Particles Most of matter is made of three subatomic particles: FNI 1E Chemistry

9. Ions • Usually atoms have the same number of electrons as protons so the charges cancel each other out. • Sometimes an atom can have more or fewer electrons than protons resulting in a net positive or negative charge. When this happens it is called an ion. • Example: Na loses an electron to form Na+ • Chlorine can gain an electron to from Cl- • We can tell what type of charge an ion is expected to have by looking at where it is in the periodic table. FNI 1E Chemistry

10. Isotopes • Atoms with the same number of protons but different numbers of neutrons • Deuterium, tritium, Carbon 12, U235 • Some isotopes are radioactive while others are stable FNI 1E Chemistry

11. The Atom Game FNI 1E Chemistry

12. http://www.shef.ac.uk/chemistry/orbitron/ Electron Orbitals 1s 2p 2s FNI 1E Chemistry

13. Chemical Bonding • Covalent bonds • Ionic bonds • Metal bonding FNI 1E Chemistry

14. Covalent bonds • Covalent bonding is when electrons are shared between to atoms or more. • The number of covalent bonds an atom is likely to form is determined by its place in the periodic table and the number of valence electrons it has. • An atom will share electrons with another atom so that it results in them both having a full valence shell. Usually this will be 8 electrons. FNI 1E Chemistry

15. Ionic bonds • When a metal and a non-metal form bonds they are typically ionic bonds where electrons are transferred from the metal to the non-metal. • Some metals will lose enough electrons to achieve a complete valence shell. • Non-metals will usually gain enough electrons to achieve a complete valence shell. • Many metals are able to form ions with more than one charge. FNI 1E Chemistry

16. Metal bonding • In metals the atoms are held together by metal bonding. Electrons can easily transfer from one atom to the next. This suggests a model of positive ions in a sea of electrons. Metals can conduct electricity because electrons flow easily in any direction. FNI 1E Chemistry

17. Covalent and Ionic Bonding FNI 1E Chemistry

18. Electronegativity and Polar Molecules • Electronegativity • This is the tendency for a type of atom to attract electron density. • Polar Molecules • If the electron density is not distributed evenly around a molecule then they are polar. • http://www.nyu.edu/pages/mathmol/library/ FNI 1E Chemistry

19. Intermolecular BondingBonding between moleculesvan der Waals forces • Hydrogen bonding • This relatively strong type of inter-molecular bonding which typically occurs between a hydrogen atom of one molecule and an electron pair or electronegative atom of another molecule. • Multiple hydrogen bonds hold the DNA double helix together. • Dipole interaction • London forces • These are induced forces caused by a temporary rearrangement of the electron clouds when molecules bump together. FNI 1E Chemistry

20. H O Hydrogen Bonding + + - - H FNI 1E Chemistry

21. H H O O H H Hydrogen Bonding FNI 1E Chemistry

22. Dipole Interaction • http://www.chemguide.co.uk/atoms/bonding/vdw.html • The partial positive and negative ends of the molecules hold the molecules together. FNI 1E Chemistry

23. London Forces London forces are induced dipoles caused by temporary rearrangement of the electron cloud. Two hexane molecules approach. The hexane molecules bump into each other. The electron clouds rearrange to form a temporary dipole. - - - + + + - - - + + + FNI 1E Chemistry

24. H H ( ) nCH2=CH2 C C n H H Polymers • Polymers are large chainlike molecules that are built from smaller molecules called monomers. • For example polyethylene is formed from ethylene: • Proteins are natural polymers. • http://www.pslc.ws/macrog.htm FNI 1E Chemistry

25. Chemical Reactions • Involve the making or breaking of chemical bonds. • Chemical reactions result in making a new substance with different properties from the original substance. FNI 1E Chemistry

26. Grains Crystal Crystals Electron orbitals Atom Unit Cell Structure of Materials FNI 1E Chemistry

27. Tissue Cells Biological Organization Organelles Membranes Proteins Nucleic Acids FNI 1E Chemistry

28. Mind Map FNI 1E Chemistry

29. Review of Chemistry • States of Matter • Atoms, Molecules and Ions • Subatomic particles • Periodic Table • Covalent and ionic bonding • Chemical reactions • Intra-molecular forces • Polymers FNI 1E Chemistry