Atoms, Molecules and Ions chapter 2

1. Atoms, Molecules and Ionschapter 2 Written by JoAnne L. Swanson University of Central Florida

2. Dalton’s Atomic TheoryDalton was an English scientist in the 1800’s who designed a theory in an attempt to explain some properties of matter. • Matter is composed of tiny particles called atoms. • Atoms of the same element are alike and atoms of different elements are different. • In ordinary chemical reactions, atoms are not created or destroyed or changed into different atoms. • Compounds form from the combination of two or more different kinds of atoms. Atoms combine in small, whole number ratios. A given compound is always composed of the same type and ratio of atoms.

3. There are two chemical Laws defined in Dalton’s theory: The Law of Conservation of Matter (or Mass) – The Law of Definite (or Constant) Composition –

4. The Subatomic ParticlesThese are the smaller particles that make up the atom. Scientists such as J.J. Thomson, Goldstien, Chadwick, Millikan, and Ernest Rutherford were mainly responsible for the discovery of the subatomic particles. Rutherford discovered- He used the GOLD FOIL EXPERIMENT (the a scattering experiment). Read pages 47-51 in your text to become familiar with the experiments leading to these discoveries.

5. DATA SUMMARY OF THE SUBATOMIC PARTICLES

6. Notice that the mass of theproton is about the same as ______________________ These two _________ particles are located in the ____________ and this makes the nucleus ___________________ The electrons are much less massive and are located outside the nucleus in the orbitals (also called shells, or electron clouds). Because it is not convenient to work with tiny masses in grams, the Atomic Mass Unit was derived. This is a unit of mass used to define very small particles. It is defined as____________________________________________ WHY? Because Carbon – 12 ________________________________________________________________________________________________________________ ________________________________________________________ ________________________________________________________

7. ISOTOPES–These are atoms of the same element that contain_________________________ Atoms of the same element must have the same number of protons, otherwise they would __________________, but they _______________________________. Neutrons do not play a role in _____________________. Isotopes exist in nature in different __________. The individual isotopes of an element are called nuclides. Hydrogen has three nuclides (isotopes) that are found in nature in different percentages. They are ______________________ ___________________________________________

9. Most of the mass of an atom comes from the __________________________________________ If you look at your periodic table, you will see a _______ __________ on each element. It increases from left to right. This is the number of _________ in that element and is called the ______________________________. The decimal number on each element is the ______________. The reason it is not 1 for Hydrogen, or 4 for Helium, or 6 for Lithium, is because it is a ___________________________ _____________________________________________ This takes into account the percentage that the isotope exists in nature, and its mass. That is, the percent is multiplied by the mass.

10. Example of how atomic mass is calculated: 1. Chlorine-35 35 amu 75 % Chlorine-37 37 amu 25 % 2. Gallium – 69 68.9 amu 60.0 % Gallium – 71 70.9 amu 40.0 %

11. The Periodic Table The GROUPS or FAMILIES are the _________________. The PERIODS are the ____________________. GROUP I IS COMPOSED OF THE ___________________ GROUP IIIS COMPOSED OF THE___________________________ B GROUPS ARE THE TRANSITION METALS GROUP VIA ARE THE CHALCOGENS GROUP VIIA ARE THE ________________ GROUP VIIIA ARE THE __________________________________

12. You might notice a zig-zag line on the right side of the table. It separates the _________________________________________ ____________________________________________________ METALS HAVE PROPERTIES OF BEING ___________________ _____________________ ____________________ ______________________________________________________ due to __________________________________ This means that the electrons in a piece of metal are able to move about among all the metal atoms that are in the piece of metal. Electrical current is defined as the flow of electrons. This mobility makes it possible for electrical current (or the flow of electrons).

13. NON METALS ARE _______________________ OF HEAT OR ELECTRICITY AND WHEN SOLID ARE BRITTLE AND DULL. SOME ARE GASES AT ROOM TEMPERATURE. ELEMENTS THAT BORDER THE ZIG-ZAG LINE ARE CALLED ____________________ THEY HAVE PROPERTIES OF BOTH ____________________ _________________________________ SO THEY ARE SEMI CONDUCTORS OF HEAT AND ELECTRICITY. METALLOIDS ARE - B, Si, Ge, As, Sb, Te ALUMINUM ( Al ) IS A ______________

14. ELEMENTS IN THE SAME GROUP HAVE SIMILAR PROPERTIES. GROUP I, THE ALKALI METALS ALL HAVE THE INTENSIVE, PHYSICAL PROPERTIES OF BEING _________________________________ THEY HAVE THE CHEMICAL PROPERTY OF REACTING VIGOROUSLY WITH WATER TO PRODUCE __ ____________________________________________________ EX. Na (s) + H2O  NaOH (aq) + H2

15. CHEMICAL COMPOUNDS ARE TWO OR MORE DIFFERENT ELEMENTS _____________ BONDED. COMPOUNDS MADE OF NON METALS ARE NEUTRAL AND ARE CALLED _______________. MOLECULES ARE FORMED WHEN TWO OR MORE NON METALS__________________________ BY OVERLAPPING THEIR ELECTRON CLOUDS (ORBITALS). THEY CAN BE THE SAME OR DIFFERENT ATOMS. ex. of Molecules: H2, F2 , O2 H2O, H2O2 CO, CO2 SO2 CCl4 P2O5 Cl2

16. IONIC COMPOUNDS ARE MADE OF ___________ PARTICLES CALLED IONS. THESE IONS ARE USUALLY COMPOSED OF ____________ and ____________________. THE ___________ ___________________ ITS ELECTRON (S) TO THE ________________FORMING A STRONG, POSITIVE AND NEGATIVE ATTRACTION (AN IONIC BOND). THIS ___________________________________________________ ___________________________________ BY CAUSING THE HIGHEST ENERGY LEVEL OF EACH PARTICLE TO BE FILLED. SINCE THESE COMPOUNDS ARE CHARGED, THEY CANNOT BE REFERRED TO AS MOLECULES (WHICH ARE NEUTRAL), SO THEY ARE SOMETIMES CALLED ______________________

17. EXAMPLES OF IONIC COMPOUNDS (METALS TO NON METALS) NaCl KF MgBr2 CaCO3 Fe2O3 metal metal metal metal metal Non metal Non metal Non metal Non metal Non metal

18. Molecular compounds have an empirical and a molecular formula. The MOLECULAR FORMULA SHOWS ____________________________________________________ The EMPIRICAL FORMULA IS A REDUCED VERSION OF THE MOLECULAR FORMULA. IT IS THE _________________ ______________________________________________ FOR EX. C4H10 IS A MOLECULAR FORMULA THE EMPIRICAL FORMULA FOR THIS COMPOUND IS C2H5 (REDUCED TO SMALLEST WHOLE NUMBER RATIOS)

19. CHEMICAL FORMULAS SHOW THE NUMBER AND TYPE OF ATOMS BONDED AND STRUCTURAL FORMULAS SHOW _____________________________________. CHEMICAL FORMULAH2O STRUCTURAL FORMULAO H H

20. EARLIER WE MENTIONED IONS (CHARGED PARTICLES). METALS MAKE _______________ CHARGED IONS. NON METALS MAKE ________________CHARGED IONS (WHEN BONDED WITH A POSITIVE METAL) POSITIVE IONS ARE CALLED __________. NEGATIVE IONS ARE CALLED __________.

21. THE CURRENT MODEL OF THE ATOM SCIENTISTS USE MODELS TO HELP THEM PREDICT HOW THINGS THAT THEY CANNOT SEE, WILL ACT. THERE WERE SEVERAL MODELS OF THE ATOM THROUGHOUT HISTORY, BUT THE CURRENT MODEL IS CALLED THE ______________ _________________________________.

22. IN EARLIER MODELS, THE ELECTRONS WERE FIRST ASSUMED TO BE DISTRIBUTED THROUGHOUT THE ATOM, AND THEN IN CIRCULAR ORBITS, THEN IN ELIPTICAL ORBITS. IT IS NOW KNOWN THAT NONE OF THESE ARE CORRECT. NOW IT IS UNDERSTOOD THAT THE ELECTRONS ARE IN AREAS OF HIGH NEGATIVE CHARGE DENSITY. THESE AREAS ARE CALLED __________________________________ _____________________________________________________ WHERE THE NEGATIVE CHARGE DENSITY ______________ _________________________________________________________ THESE ORBITALS HAVE DIFFERENT SHAPES AND HAVE DIFFERENT ENERGIES ASSOCIATED WITH THEM.

23. THE FARTHER AWAY FROM THE NUCLEUS THE ORBITAL IS LOCATED, THE ______________________. EACH PERIOD ON THE PERIODIC TABLE REPRESENTS A __________________________ THAN THE ONE PREVIOUS. THESE ARE CALLED PRINCIPLE ENERGY LEVELS (PEL). ELECTRONS FILL ORBITALS FROM _____________ ________________ ENERGY. HYDROGEN has

24. BECAUSE ATOMS ARE NEUTRAL, as the number of PROTONS INCREASE, _________________________. (POSITIVE AND NEGATIVE CHARGES ARE EQUAL). CALCIUM, Ca, HAS 20 PROTONS AND 20 ELECTRONS. _____________________________________________________________________________________________________________________________________________________________________WE CAN LOOK AT THE PERIODIC TABLE AND KNOW WHICH ORBITALS HAVE ELECTRONS IN THEM. THERE ARE DESIGNATIONS CALLED QUANTUM NUMBERS THAT TELL __________________________________ _______________________________________________________ _______________________________________________________ ______________________________________________________

25. THE QUANTUM NUMBERS DESIGNATE THE ______ _______________________________________________ _______________________________________________ THE ORBITAL (shells) SHAPES HAVE LABELS s, p, d, f. GROUPS I AND II ARE WHERE ____ ORBITALS FILL. THE ‘B’ GROUPS ARE WHERE ____ ORBITALS FILL. GROUPS IIIA – VIIIA ARE WHERE __ ORBITALS FILL THE BOTTOM TWO PERIODS ARE WHERE ___ FILLS.

26. THE ‘s’ ORBITALS ARE ______________________. THERE IS _______________________________________________. THE ‘p’ ORBITALS MAY BE THOUGHT OF AS PEANUT SHAPED. THERE ARE _______________________________ _________________________________________________. THE ‘d’ ORBITALS ARE LIKE TWO SETS OF ‘p’ ORBITALS, AND SOME ARE MORE COMPLEX. THERE ARE ______ ‘d’ ORBITALS IN EACH ENERGY LEVEL, STARTING WITH THE THIRD ENERGY LEVEL. BUT THEY DON’T START FILLING _______________________________________. THE ‘f’ ORBITALS ARE COMPLEX AND THERE ARE ______ ‘f’ ORBITALS IN EACH ENERGY LEVEL STARTING WITH ENERGY LEVEL _____. THEY DON’T START FILLING WITH ELECTRONS UNTIL AFTER ___ _____________.

27. ELECTRON CONFIGURATIONS TELL THE LOCATION AND ORIENTATION OF EACH ELECTRON IN AN ELEMENT. H 1s1 He 1s2 Li 1s2 2s1 Be 1s2 2s2 B 1s2 2s22p1 C 1s2 2s22p2 F 1s2 2s22p5 The superscripts Ne 1s2 2s22p6

28. ELEMENTS IN THE THIRD ENERGY LEVEL HAVE EMPTY ‘d’ ORBITALS. THESE ORBITALS FILL WITH ELECTRONS AFTER THE __ ORBITAL FILLS. THE ‘f’ ORBITALS ARE EXISTING IN THE FOURTH ENERGY LEVEL, EMPTY, BUT THEY DON’T FILL WITH ELECTRONS UNTIL AFTER THE __ AND __ ORBITALS FILL. NOTICE THAT THE INERT GASES ALL END WITH ____(EXCEPT FOR He WHICH ENDS IN ___). THEY ALL HAVE THEIR HIGHEST ENERGY LEVELS ________ _____ _____________. THEY ARE STABLE (INERT, UNREACTIVE) BECAUSE OF THIS!

29. HAVING THE HIGHEST ENERGY LEVEL FILLED WITH ELECTRONS MAKES ELEMENTS ____________________. ATOMS WILL GAIN OR LOSE ELECTRONS TO ________________________ _________________________________. ENERGY IS ASSOCIATED WITH THE _____ _____________________ OF ELECTRONS. IF AN ATOM LOSES ELECTRONS, IT LOSES ____________________________. NOW ITS PREVIOUS ENERGY LEVEL IS FILLED.

30. ELEMENTS IN GROUP I WILL ___________________ RATHER THAN GAIN 7. ELEMENTS IN GROUP II WILL ___________________ RATHER THAN GAIN 6. ELEMENTS IN GROUP IIIA WILL USUALLY ____________. ELEMENTS IN GROUP IVA VARY. ELEMENTS IN GROUP VA WILL OFTEN _______________ ELECTRONS ELEMENTS IN GROUP VIA WILL _____________ ELEMENTS IN GROUP VIIA WILL ____________ ELEMENTS IN GROUP VIIIA HAVE A FILLED ENERGY LEVEL AND ___________________________________.

31. Definition – An Allotrope – is a substance _____________ __________________________.ex. Carbon exists as_________ and ____________Phosporus can be white or red (each with different properties)Oxygen exists as ________ and ________. Look in your text for the allotropes of another element.

32. The Atomic Mass of an element: • The atomic mass of H is 1.0079 amu • The atomic mass of Li is 6.941 amu • The atomic mass of Cr is 51.996 amu This means that one atom of H weighs 1.0079 amu, etc. We cannot count atoms accurately so we have a number that represents lots of atoms (easier to work with). That number is called _________ _______________________ and is equal to _______________________particles and has a mass in grams, called the ____________. This mass is numerically equal to ______________ but is measured in grams because it is a measure of not one atom, but a mole of atoms.

33. mass to mole conversions • If I have one mole of H, it now has a mass of 1.0079 grams • If I have one mole of Li, it now has a mass of 6.941 grams • If I have one mole of Cr, it now has a mass of _____________________ So one atom is 1.0079 amu, one mole is _________________________.

34. Convert grams to moles • ex. How many moles are 20.51 grams of H? ex. How many grams are 2.15 moles of H?

35. convert grams to atoms • How many atoms are there in 15.5 grams of H? ex. How many grams does 5.95 x 1025 atoms weigh?

36. convert moles to atoms • How many atoms are there in 3.51 moles of H? ex. How many moles do 5.55 x 1031 atoms make?

37. The beginning of chapter 3 starts here. The rest of chapter three will follow on a separate button when uploaded.

38. USING THE PERIODIC TABLE TO DETERMINE CHARGES ON IONS (AND THEN PREDICT CHEMICAL FORMULAS)

39. IF AN ATOM LOSES ONE ELECTRON, IT IS LEFT WITH ONE EXTRA PROTON. THIS GIVES THE ION A _________ _______________________________ IF AN ATOM GAINS ONE ELECTRON, IT THEN HAS AN ELECTRON IN EXCESS OF ITS PROTONS. THIS GIVES THE ION A ___________________________. WHAT CHARGES WOULD THE FOLLOWING ATOMS HAVE WHEN THEY BECOME IONS? O Mg N

40. REMEMBER, ONLY ELECTRONS ARE GAINED OR LOST. PROTONS MUST REMAIN THE SAME IN AN ELEMENT OR IT WILL NOT BE THE SAME ELEMENT.

41. IONIC COMPOUNDS ARE FORMED FROM THE TRANSFERRING OF ELECTRONS FROM ________________ ___________________________. NaCl - HERE THE SODIUM __________ AN ELECTRON AND THE CHLORINE ________ THAT ELECTRON. THE SODIUM THEN HAS A ____ CHARGE, THE CHLORIDE ION NOW HAS A ____ CHARGE. THESE TWO IONS ARE VERY STRONGLY HELD TOGETHER BY THE ELECTROSTATIC FORCES THAT ATTRACT A + TO A - Mg WILL ______________ ELECTRONS. Cl WILL _______________. IT TAKES ______ CHLORINES TO ACCOMMODATE ONE Mg. MgCl2

42. WILL ALUMINUM GAIN OR LOSE ELECTRONS, AND HOW MANY??? ____________________________________________. WHAT WILL THE CHARGE BE ON A SULFIDE ION??? _______________________________________________________ SO, WHAT WILL THE FORMULA BE FOR ALUMINUM SULFIDE??? IF Al+3 AND S-2

43. NAMING DIFFERENT TYPES OF CHEMICAL COMPOUNDS(CHEMICAL NOMENCLATURE) • THERE ARE THREE QUESTIONS TO ASK YOURSELF IN ORDER TO NAME AN INORGANIC, CHEMICAL COMPOUND: • IS THE FIRST ELEMENT A NON-METAL??? • IS THE FIRST ELEMENT A GROUP I, II, OR IIIA METAL??? • IS THE FIRST ELEMENT A TRANSITION METAL??? • THE ANSWERS TO THESE QUESTIONS ARE HOW TO DETERMINE THE PROPER WAY TO NAME THE COMPOUND.

44. IF THE FIRST ELEMENT IS A NON-METAL THIS MEANS THE COMPOUND HAS A NON-METAL BONDED TO A NON-METAL. ITS A _______________ _________________. DIFFERENT NUMBERS OF NON-METALS BOND TO EACH OTHER. FOR EX. CO, CO2 , H2O, H2O2 WE USE ______________________________________________ ATOM IS BONDED. EX. CO IS CARBON MONOXIDE (THE PREFIX MONO MEANS ONE). CO2 IS CARBON DIOXIDE (THE PREFIX ‘DI’ MEANS TWO)

45. A COMPLETE LIST OF THE PREFIXES THAT WE WILL USE: • MONO ONE • DI TWO • TRI THREE • TETRA FOUR • PENTA FIVE • HEXA SIX • HEPTA SEVEN • OCTA EIGHT • NONA NINE • DECA TEN

46. SOME EXAMPLES: PO5__________________________________________ ____________________________________________________. P2O5 _________________________________ CCl4 ___________________________________ SF6 ___________________________________

47. NOTICE THAT IN EACH NAME THE SECOND ELEMENT, THE ANION, ALWAYS ENDS IN ‘IDE’…. CHLORIDE FLUORIDE OXIDE

48. WHEN THE FIRST ELEMENT IS A GROUP I, II, OR IIIA METAL WE SIMPLY NAME THE ________________________________ ___________________________. IF THE NON-METAL IS A POLYATOMIC ION, (A CHARGED GROUP OF ATOMS), THEN WE NAME THE METAL FOLLOWED BY THE NAME OF THE POLYATOMIC ION.

49. EXAMPLES: NaCl MgCl2 K2S AlN Al2O3 SrF2 LiNO3 Ca(NO3)2 K3PO4 Al(C2H3O2)3

50. THE FIRST ELEMENT IS A TRANSITION METAL THE WORD TRANSITION MEANS ‘_____________’. THE CHARGES CAN VARY, (___________) ON TRANSITION METALS, SO, WE HAVE TO STATE THE CHARGE IN THE NAME. WE NAME THE METAL, FOLLOWED BY ______________, (WHEN WRITING, THE CHARGE IS PUT IN PARENTHESIS, IN ROMAN NUMERALS), THEN WE NAME THE NON-METAL OR POLYATOMIC ION.