1. (Teknik) Atoms, Molecules, and Ions.pptx

atom, molekul, dan ion

1. ATOMS, MOLECULES, AND IONS 1 st MEETING – CHEMISTRY: Andriana Kusuma Pertiwi, M.Si .

2. Outline 1 The Atomic Theory The Structure of the Atom Atomic Number, Mass Number, and Isotopes The Periodic Table Molecules and Ions Chemical Formulas Naming Compounds Introduction to Organic Compounds

3. Everything in our world is made up of atoms What is an atom? Water Air 2 Metal Wood Plastic Animal Rock Oil Bacteria Human Cell phone Vehicle Clothes Fruits

4. 3 What is an atom? The smallest unit of an element that has all the properties of that element. Cannot be broken down into smaller particles by ordinary processes. Consists of a central nucleus ( proton and neutron ) surrounded by one or more electrons .

5. 4 The nucleus contains the following subatomic particles : Protons - positively (+) charged particles Neutrons - particles that have no charge (neutral), but contribute to the atom’s mass Electron cloud - an area around the nucleus where electrons are likely to be found orbiting the nucleus in several energy levels Atomic Structure

6. 5 Multiple energy levels in the electron cloud completely surround the nucleus. Electrons follow a specific order to fill the energy levels. The electrons in the outermost energy level are called valence electrons . We will go into more detail about the importance of valence electrons in our next unit. Outer Structure of an Atom Maximum of 2 electrons Nucleus Maximum of 8 electrons Maximum of 8 electrons* *Applies to the first 18 elements only

7. 6 Atomic Structure Discovery of the components of the atom and subsequent modeling of the atomic structure led to explosive advances. The nature of the chemical bond Information about how reactions work N ew analytical (measuring) methods CHEMISTRY Isotope tracers Ne w d r u g s Cancer treatments Ne w c e l l s c r ee n i n g m e t h o d s MEDICINE ENERGY Nuclear fission Nuclear fusion P o w e r p l a n t s Understanding of the nature of t h e s u n , p l a n e t s , s t a r s , e tc Weapons Electronics / computer development Ne w mo l e c u l e s y n t h e s i s Emergence of the field of Nuclear Chemistry

8. 7 Dalton’s Atomic Theory All matter is made up of tiny, indivisible particles called atoms All atoms of a specific element have the same size, mass, and other properties Atoms of different elements have different sizes, masses, and other properties Atoms of different elements can combine in whole number ratios to form chemical compounds In chemical reactions, atoms can be combined, separated, or rearranged

9. 8 Discovery of The Electron In 1897, J.J. Thomson used a cathode ray tube to deduce the presence of a negatively charged particle. Cathode ray tubes pass electricity through a gas that is contained at a very low pressure.

10. or “ P l u ms” “ pudd i ng ” J.J. Thomson in Philosophical Magazine, 1904 “... the atoms of the elements consist of a number of negatively electrified corpuscles enclosed in a sphere of uniform positive electrification, ... “ Thomson’s Atomic Model 9

11. Rutherford’s Findings Rutherford’s Gold Foil Experiment Showed that the positive charge of the atom MUST be concentrated in a tiny, yet heavy volume he called the nucleus Almost ALL of the mass of the atom is in the nucleus Very lignt electrons surround this nucleus The volume that an atom occupies is mostly empty space 10

12. Bohr Model Niels Bohr E l e c t r o n s i n w e l l d e f i n e d “ p l a n e t a r y ” o r b i t s or paths around the nucleus S t i l l g oo d f o r v i s u a l i z i n g t h e e n e r g y t r a n s i t i o n s of electrons Overall spherical shape E l e c t r o n s o cc u p y c e r t a i n o r b i t a l v o l u m e s o r clouds The type of cloud it occupies depends upon its energy or distance from the nucleus 11

13. Quantum Mechanical Model 12 Found that electrons live in fuzzy regions or “clouds” not distinct orbits Improved on Bohr’s findings Electron location can not be predicted The electron can be “anywhere” in a certain energy level Electrons can be found anywhere in these “shells” The electrons are still quantized no electrons can be found here Schr o dinger Heisenberg

14. ? Identify the atomic model! 13 A B C D E

15. 14 Atomic Number and Mass Number # of protons + # neutrons = mass number # of protons = atomic number A carbon atom with 6 protons and 6 neutrons has a mass number = 12 The atomic number of carbon is 6 Number of electrons will EQUAL the number of protons for an atom with NO NET CHARGE

16. A molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical forces. H 2 H 2 O NH 3 CH 4 A diatomic molecule contains only two atoms H 2 , N 2 , O 2 , Br 2 , HCl, CO A polyatomic molecule contains more than two atoms O 3 , H 2 O, NH 3 , CH 4 16

17. An ion is an atom, or group of atoms, that has a net positive or negative charge. Cation – ion with a positive charge If a neutral atom loses one or more electrons it becomes a cation . Anion – ion with a negative charge If a neutral atom gains one or more electrons it becomes an anion. Na 11 protons 11 electrons Na + 11 protons 10 electrons Cl 17 protons 17 electrons Cl - 17 protons 18 electrons 17

18. A monatomic ion contains only one atom A polyatomic ion contains more than one atom Na + , Cl - , Ca 2+ , O 2- , Al 3+ , N 3- OH - , CN - , NH 4 + , NO 3 - 18

19. 13 protons, 10 (13 – 3) electrons 34 protons, 36 (34 + 2) electrons Do You Understand Ions? How many protons and electrons are in ? Al 27 13 3+ How many protons and electrons are in ? Se 78 34 2- 19

20. 20 Isotope An atom with the same atomic number (same number of protons) but a different number of neutrons Isotopes of the same atom have approximately the same chemical properties PROTON ELECTRON NEUTRON ? The ATOMIC MASS is a w e i g h t e d a v e r a g e o f t h e mass for each isotope .

21. Do You Understand Isotopes? How many protons , neutrons , and electrons are in.. He 3 2 C 14 6 C 12 6 C 13 6 He 4 2 N 14 7 N 15 7 O 18 8 O 16 8 O 17 8 Ne 20 10 Ne 21 10 Ne 22 10 21

22. Period Group Alkali Metal Noble Gas Halogen Alkali Earth Metal The Periodic Table 22

23. Molecular Models 23

24. A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance. An empirical formula shows the simplest whole-number ratio of the atoms in a substance. H 2 O H 2 O molecular empirical C 6 H 12 O 6 CH 2 O N 2 H 4 NH 2 24

25. 2. Changing the name of nonmetals: Metal + non metal-ide = name of ionic compound Examples: The name of NaCl : The name of MgBr 2 : Sodium + Chlor-ide = Sodium chloride Magnesium + Brom-ide = Magnesium bromide 1. The names of metals do not change. RULES FOR NAMING IONIC COMPOUND 25

26. 1. NaF sodium fluoride 2. MgO magnesium oxide 3. SrCl 2 strontium chloride 4. Li 2 S lithium sulfide 5. CaO calcium oxide 6. KI potassium iodide 26

27. There are also ions that form after elements have shared electrons. These ions are known as polyatomic ions , and each polyatomic ion already has a name. 27

28. 1. NH 4 F ammonium fluoride 2. CaSO 4 calcium sulfate 3. Mg(NO 3 ) 2 magnesium nitrate 4. NaOH sodium hydroxide When polyatomic ions are used, simply use the name of the polyatomic ion in the compound. 28

29. Name the ionic compounds that are found on your notes. calcium chloride potassium sulfide cesium chloride barium oxide ammonium chloride potassium permanganate magnesium sulfate sodium bromide aluminum phosphide 29

30. Some elements have more than one cation form. These elements are known as transition metals. 30

31. Remember that the names of transition metals include their charge because their charges are less predictable. What are the charges of the transition metals below: Iron (II) _______ Iron (III) _______ Copper (II) _______ Copper (I) _______ Tin (IV) _______ Tin (II) _______ Lead (II) _______ Lead (IV) _______ +2 +3 +2 +1 +4 +2 +2 +4 We know they are positive because metals are always positive. 31

32. 1. FeCl 2 Iron (II) chloride 2. FeBr 3 Iron (III) bromide 3. Cu(NO 3 ) 2 Copper (II) nitrate 4. CuSO4 Copper (II) sulfate When transition metals are used, simply use the name of the metals + charge in romawi + non metals in the compound. 32

33. You can also determine the formula of an ionic compound from its name. To do this, you will need to use what you already know about the Periodic Table. magnesium iodide Step 1: Write the symbol of the metal ion. Step 2: Write the symbol of the nonmetal ion. Step 3: Determine the charges using the periodic table. Step 4: Determine the formula from the ions. Mg I +2 - MgI 2 33

34. This is just as easy to do with polyatomic ions. You just need to use the name of the polyatomic ion. strontium nitrate Step 1: Write the symbol of the metal ion. Step 2: Write the formula of the polyatomic ion. Step 3: Determine the charges using the periodic table and the table of polyatomic ions. Step 4: Determine the formula from the ions. Sr NO 3 +2 - Sr(NO 3 ) 2 34

35. The charges of the transition metals are important when you are determining the formula of an ionic compound. iron (III) oxide Step 1: Write the symbol of the cation. Step 2: Write the symbol of the anion. Step 3: Determine the charges using the periodic table and the roman numerals. Step 4: Determine the formula from the ions. Fe O +3 -2 Fe 2 O 3 35

36. RULES FOR NAMING MOLECULAR COMPOUND (prefix) nonmetal + (prefix) nonmetal-ide = name of molecular compound N 2 O 4 Step 1: Write the name of the first nonmetal. Step 2: Write the name of the second nonmetal changing its ending to -ide . Step 3: Add prefixes to specify how many of each element are present. nitrogen oxide dinitrogen tetroxide 36

37. Rules for Using Prefixes Rule 1: Prefixes are only for BINARY COVALENT compounds. Rule 2: The prefix mono- is never used on the first element of a binary covalent compound. Without a prefix it is assumed that there is only 1. Rule 3: Remove the -o or -a from a prefix before adding it to oxide. Example: CO 2 is carbon dioxide, and not monocarbon dioxide. Example: CO is carbon monoxide, and not carbon monooxide. 37

38. How would you write each of the prefixes in front of oxide? mono- ____________ di- ____________ tri- ____________ tetra- ____________ penta- ____________ hexa- ____________ hepta- ____________ octa- ____________ nona- ____________ deca- ____________ monoxide dioxide trioxide tetroxide pentoxide hexoxide heptoxide octoxide nonoxide decoxide Remember: Remove the -o or -a from a prefix before adding it to oxide. Leave -i alone. 38

39. Name the binary covalent compounds that are found on your notes. carbon dioxide carbon disulfide phosphorous tribromide phosphorous pentabromide diphosphorous pentasulfide dinitrogen monosulfide silicon disulfide nitrogen tribromide dinitrogen tetrachloride 39

40. Because of the prefixes, it is very easy to go from the name of a binary covalent compound to its formula. dinitrogen tetrafluoride Step 1: Write the symbol of the first nonmetal and the subscript that matches the prefix. Step 2: Write the symbol of the second nonmetal and the subscript that matches the prefix. N 2 F 4 40

41. Write the formulas of the binary covalent compounds in your notes. CCl 4 PCl 5 N 2 O CS BH 3 S 2 Br 6 SiS 2 PI 3 NCl 3 IF 7 N 2 O 4 PCl 3 CO ICl S 4 N 4 H 2 O ClF 5 NO 2 41

42. An acid can be defined as a substance that yields hydrogen ions (H + ) when dissolved in water. HCl Pure substance, hydrogen chloride Dissolved in water (H + Cl - ), hydrochloric acid An oxoacid is an acid that contains hydrogen, oxygen, and another element. HNO 3 nitric acid H 2 CO 3 carbonic acid H 2 SO 4 sulfuric acid HNO 3 42

43. Naming Oxoacids and Oxoanions 43

44. A base can be defined as a substance that yields hydroxide ions (OH - ) when dissolved in water. NaOH sodium hydroxide KOH potassium hydroxide Ba(OH) 2 barium hydroxide 44

45. Hydrates are compounds that have a specific number of water molecules attached to them. BaCl 2 •2H 2 O LiCl •H 2 O MgSO 4 •7H 2 O Sr(NO 3 ) 2 •4H 2 O barium chloride dihydrate lithium chloride monohydrate magnesium sulfate heptahydrate strontium nitrate tetrahydrate CuSO 4 •5H2O CuSO4 45

46. Organic chemistry is the branch of chemistry that deals with carbon compounds. C H H H OH C H H H NH 2 C H H H C OH O methanol methylamine acetic acid Functional Groups 46

47. SUMMARY?

48. THANK YOU! “The task is to think differently about what everyone already sees.” –Erwin Schrodinger