Chemistry

1. Chemistry

3. ELEMENTS • Matter: Anything that has mass and takes up space. Matter is made up of substances called Elements. PROPERTIES OF ELEMENTS 1. Physical: Color, density, hardness, streak, etc. 2. Chemical: Reaction with other substances

4. Atom • Atom: Smallest unit of an element. Same chemical and physical properties. • Protons • Neutrons • Electrons Mass of particlep+= n°>>e¯ 1.6726 × 10¯²⁷ Kg 1/1840 of p+ Nucleus

5. Periodic Table • 92 Naturally occurring • 25 Synthetic ( man-made ) Atomic Mass = # of p + plus # of n° Atomic Number = # of p + = # of e ¯

7. Questions H Name the following elements: • Lightest element: • Heaviest Naturally occurring element: • Element with 18 protons: • Element with 11 electrons: • Element named after this guy! U Ar Na Es

8. PracticeAtomic Number = # of p + = # of e ¯ Atomic Mass = # of p + plus # of n° 92 146 92 14 28 14 10 10 10 16 32 16 18 22 18

9. HW • The Elements

10. Chemical Reactions • Exchange/sharing of electrons between elements. • Chemical reaction/bonding of elements create new substances/compounds. water molecules

11. Electrons and Energy Levels

12. Energy Levels/Shells

13. Energy Level/Shell Capacity Electron Capacity = 2 n² n = Energy Level

14. Bohr Model Element Symbol Atomic Number ______ Mass Number ______ Number of p+ ______ Number of n ______ Number of e- ______

15. Bohr Models • Complete Bohr models for the following elements: • Oxygen • Carbon • Sodium • Helium • Chlorine • Aluminum • Potassium • Nitrogen

16. Bohr Model Element Symbol Atomic Number ______ Mass Number ______ Number of p+ ______ Number of n ______ Number of e- ______ Number of e- in the last level ______

17. Valence Electrons • Half Arcs Ve¯ Electrons on the outermost shell 14 8 4 2 Si Valence electrons

18. Valence Electrons • The number of electrons on the outermost shell determine if an element is going to react with other elements or not. • If the outermost shell is not full Reactive • If the outermost shell is full Non- Reactive/Inert

19. Review Reactive needs 5 more e¯ 14: Silicon 2, 8, 4 needs 4 more e¯ Reactive

20. Chemical Reactions/ Bonds

21. Types of Chemical Bonds • Covalent Bonding Valence electrons are shared between atoms.

22. Ionic Bonding Valence electrons are exchanged. Atoms either gain or lose electrons.

23. Electrical Charge of Stable Atoms • Nitrogen atom • 7 p+ • 7 n ° • 7 e ¯ • Nucleus: p++ n° = 7 ⁺ + 0 = 7 ⁺ • e¯ = 7 ¯ • Stable Atom: Nucleus + e¯= 7 ⁺ + 7 ¯ • Total charge = 0

24. Silicon Nitrogen Iron

25. Atomic Charge Practice 5 17 8 13 18 8 6 14 13 5 17 8 5 17 13 8 17 13 8 5 0 0 0 0

26. Stable Atoms • Electrical Charge of Stable Atom is always ZERO. • Equal number of p+ and e¯ = 0 charge

27. Ions • When atoms have different numbers of positive • ( ) and negative ( ) charges, the atom will have an electrical charge. • Electrically charged atoms are called ions. protons electrons

28. Ions • Ionic Bonding lose/gain e ¯ • If an atom loses e ¯ • If an atom gains e ¯ e¯< p+ ion+ e¯ > p+ ion ¯

29. 11 Na # p = # e = 8 O # p = # e =

30. e¯ < p+ + ion + 1 8 Lose e 2 11 Na # p+= 11 # e¯ = 11 8 O # p+ = 8 # e¯ = 8 =10 - e¯ > p+ 8 2 6 ion ¯ Gain e = 10

31. Isotopes Isotopes • Atoms of the same element ( equal number of protons ) that have different number of neutrons. • Ex. Chlorine ¹⁷ Chlorine ¹⁷ 17 p +,17 n ° 17 p +,18 n ° 34 Atomic mass 35

32. Radioactivity • An Isotope with unequal number of protons and neutrons in its nucleus is unstable. It will release particles ( p + / n ° ) from its nucleus in order to end up with equal numbers of p + and n °. This process of radiation ofparticles from the nucleus is called Radioactivity.

33. Radioactivity • As an isotope releases particles, its atomic mass and its atomic number can change. This means that it can change ( Decay ) into atom of another element. Uranium Lead Decay Unstable atom Stable atom

34. Half-Life • The time it will take for half of the atoms of the original Parent element to decay into atoms of another element Daughter, is called Half-Life. Parent ½ Daughter+ ½ Parentunstable atoms stable atoms TIME

35. Half-Life TIME Parent ½ Parent, ½ Daughter U-238U-238 Pb-206 Daughter Pb-206

36. Uranium-238 to Lead-206

37. Half-Life Graph • Lab

38. Nuclear Energy

39. Physical States Of Matter Physical States Matter can not be destroyed. Matter can change into physical forms of Solid, Liquid, & Gas. The physical state of a matter depends on the strength of the atomic bonds compared to the energy of the atoms. The more energy atoms/particles absorb the more they vibrate and try to move.

40. Physical States

41. Solid • Low particle energy/motion • Strong bond • Particles remain in same place. • Dimensions remain unchanged. • Definite Shape & Volume

42. Liquid • Melting Point Particles absorb energy bonds are now weaker compared to the particle motion. • Particles can move around but are still held together by the bonds. • Distance between the particles do not change. • Definite Volume • No definite Shape

43. Gas • Boiling Point Particles absorb more energy. • Evaporation No bonds exist. • Particles are free to move. • No definite Dimensions. • No definite Shape or Volume

44. Plasma • Highly energized gas particles • Colliding • Loss of e ¯ particles • Ions+ • Glowing cloud of ions+ and e ¯ • Lightning, Neon lights, fire

45. Thermal Energy GainLose SOLID LIQUID GAS Melting Sublimation Freezing Frost Condensation Evaporation

46. States of matter Graph

47. Review

49. Practice • Lab: Elements of the Earth’s Crust Pie Chart