Structure of the Atom

ChemQuest 8 Name: ------------Date: _______ Hour: __ Information: Structure of the Atom Note the following symbols: (they are not to scale) 0 =proton (positive charge) •=electron (negative charge) 8 =neutron (no charge) The following three diagrams are hydrogen atoms: • • 0 • «) The following three diagrams are carbon atoms: • • -� . • • • • • � � • • • • • • � • • • (6 protons, 6 neutrons) (6 protons, 7 neutrons) (6 protons, 8 neutrons) Notice the type of notation used for atoms: AX z X =chemical symbol of the element Z = "atomic number" A = "mass number" 1 � C, 1 � C, and ': C are notations that represent isotopes of carbon. : H , ; H and � H are notations that represent isotopes of hydrogen. The part of the atom where the protons and neutrons are is called the_ nucleus. Copyright 2002-2004 by Jason Neil. All rights reserved. To make copies permission must be obtained from www.Chemistrylnquiry.com Critical Thinking Questions 1. How many protons are found in each of the following: : H ? in � H ? in � H ? 2. How many neutrons are found in each of the following:: H ? in � H? in � H ? 0 ✓ JI I 3. How many electrons are found in each of the following: : H ? in � H? in� H ? 4. What structural characteristics do all hydrogen atoms have in common? OY\€ ?V1>1 0(\ . Of\ f e \ R C -ryt)v\ 5. What structural characteristics do all carbon atoms have in common? sI x �:>.� s I e I e c �Yl.Y'i s s 1x 6. What does the mass number tell you? Can you find the mass number of an element on the periodic table? 0 ?YD1(Y1S + :t:\1Y6't1 S ) * \/ D\\ (Cl f\ V1 ()'\ flev-.. h '{)() --\-V' 1 � Of\ hrlA e ?1 ( VY1 u )� t)f °' w no If ·.4- 1. What does the atomic number tell you? Can you find the atomic number of an element on the periodic table? t\: 'TI.X1 _s ?Vl) 1 �e S 8. Define the term isotope. 0.,-n.YV'I� 1J0! c\\ { J-c. r tt1� =It S Cl,,VY) e ci tln-f v'\f tA)- t'Of\ � °b 9. How does one isotope of carbon differ from another isotope of carbon? eh %ere f) ,/-- V\ lA_,VY) \?( I" ob V\ e L d V' (Y') s, Information: Atoms, Ions, Masses of Subatomic Particles The atomic mass unit (amu) is a special unit for measuring the mass of very small particles such as atoms. The relationship between amu and grams is the following: 1.00 amu= 1.66 x 10-24g Note the following diagrams comparing atoms and ions. ••• • • • •• Atom \ 9 �otons ---► � eutrons • j 19 9p mass= 18.9980 amu ••••• • • � •• • • . Ion • ••• • • • 19 -1 9p mass= 18.9985 amu Ion Atom 12 protons 12 neutrons ► 24M g 12 mass= 23.9978 amu � � �rotons • \o/eutrons • • •• 12 protons 12 neutrons 24M +2 12 g mass= 23.9968 amu Critical Thinking Questions 10. What is structurally different between an atom and an ion? Note: This is the ONLY structural difference between an atom and an ion. � d -{ {{ f e V\ ··\ itff l i Yl.)'1,$ er; /l 11. In atomic mass units (amu), what is the mass of an electron? I 0005 0-,VYlU.. 12. Is most of the mass of an atom located in the nucleus or outside the nucleus? How do you know? I Y\�,de V\ Ovvf --KAe V\ l.,l de lA.S I ve 1 . +n e e - on -+-V\e t 1 +t 1 -e VViO s s 0L,0r srde 13. If protons and neutrons have the same mass, what is the approximate mass of a proton and 1 neutron in atomic mass units (amu)? CUM LA N \ 14. The mass of and 13? 14c 6 \Its is about 14 amu. Does this agree with what you determined in questions 11 e. - 15. The charge (in the upper right hand comer of the element symbol) is -1 for a fluorine ion. Why isn't it+1 or some other number? V\Cl \If 0.... Ct,-n V (' (,,� CL,( q lt \!\(AS OA-e - e.xtrtA elfC,1YM V'\€.9 16. What is the charge on every atom? Why is this the charge? Vle tA.,--1 r-0-..,\ . so,)m f> cl:\- 17. How do you detennine the charge on an ion? t(Y\'I r (;__xe fV\ f' � °D aD {)Y'{)�s e � II"\ d O..Y, d -f I P c h't,/\ \ pv l)f(Y\ s 0... If'\ c\ t?. l (> C \) ovir 18. An oxygen ion has a -2 charge. (Use your periodic table if necessary) a) How many protons does the oxygen ion have? g b) How many electrons does the oxygen ion have? Name________Hour__ Atomic Theory Homework Chemical symbol 7L. 3' 31P 15 45 Sc 21 Mass number 237N 93 p 16028 3 0 31 10 10 \\o IS 0 21 2.t\ 2.\ 2� 2\ 2°1 13 \ 2 °' 5� CS� 35 0 2 31 �3 sz ' ; N 35h H '2.f56 2.1o e 14 B9 g9 � 39 IO � �7 A1�-r \ 131 fuit 5 lo llq S() W 3� SYI jf 1 -' Net charge L\ /ID 52cr6+ 24 Number of electrons 3 \ \o 70G a 3+ 31 Number of neutrons 3 lo� 131xe 54 Number of protons l �s 64Cu 29 Atomic number g 93 � 3\ 3\ 2.L\ 1 2"\ 7 71 \�� i 3� i� -, 26 21o 30 3q 39 50 41 108 �l 137 56 5b 119 SD 50 80 34 34 s� 9:> 0 0 lO 2- 2� 3t \i b+ 10 3- 2� 2+ 39 81 4lo 5� lo9 4lo 5D 3to 61 0 0 1+ 2+ 0 2- Atomic Structure 1. Consider the three fundamental particles: electrons (e·), protons (p+), and neutrons (n°) a. Which has the smallest mass? c. Which is found outside the nucleus? b. Which is uncharged? nO e- e- d. Which 2 have nearly the same mass? -p+ � V') b 2. Complete the following table using the information given Chemical symbol Atomic number 222 Rn 86 1378a2+ 56 Sto �3? By 35 J\ g zz. 1q � 3 TiI· t K i0 22 l °' Number of protons i \11 5lo 22 35 Atom (ion) of element Number of electrons Number of protons Number of neutrons Mass number a 5 5 5 10 Number of neutrons 80 26 d 12 10 10 20 C 0 1- �5 20 18 9 10 10 20 0 2.+ 5\ 3lo 39 Net charge \�lo 5� 22 i '3 b 7 7 7 14 Number of electrons ?� 222 \37 \� 3. Consider the table below a. b. c. d. Mass number e 7 7 8 15 1+ f 6 5 6 11 g 9 9 10. 19 e I C\ Which of the species above are electrically neutral? Q_ I J I Which are negatively charged? dI Which are isotopes of the same element? Q..._ + _f- 1 b 4 Using the periodic table, write the conventional symbol for b, d, and f f b e 2.oN i d= I() (: f=----"-_ � B__ - _ 4. How does the number of protons compare to the number of electrons in: a. An anion? '('(\(:Y(e �V\Gl-1/'I � b. A cation? e- 5. How do the chemical properties of carbon-12 and carbon-14 compare? 6. How do the physical properties of carbon-12 and carbon-14 compare? mc.,rt p1 "'rhC<..A'le- ph � Si ccd * C�V\!\ 1 cc� l. 'P Vl) ?e ( -\7 -e s cu-e_ +11\e s(A_.m IS01W.5 e c/' 0 7. Consider the data table below Atom (ion) of element Number of electrons Number of protons Number of neutrons b 13 10 a 12 12 12 14 d 12 12 13 C 11 10 12 e 14 14 14 g 10 10 10 f 15 18 16 a. Which of the above species are negatively charged? b , • C. b. Which species are isotopes of the same element? ()_ c. Give the conventional chemical symbol (including charge) for species A, B, and F. -rc\ �A 2A'"1 t.. I f.. 3 -3� 3� ' A I/"'" 1 I 2 I"\(). b= I O / \/ f= -�---I� ;,) 8. What must be done to a neutral chlorine atom in order for it to change into a er ion? Be specific. a= 2� \ e 1-e C1r1Y' fY\Wt 9. Complete the following table Chemical symbol 1 f� \( + Atomic number 19 t Pelz+ 325216 2.,()1 B f3 Number of neutrons Mass number 60 106 Lllo I lo 3-,- 83 20 \\o Number of electrons 3 9 \� 1+ �4 32. 2+ ll 20� 126 Net charge 2- �b 3+ 0 10. Which two fundamental particles (e·, p , n ) have the same mass? __p1-t __-+__ _____ 11. Which particle accounts for virtually all of any atoms volume? ___e_-____ 12. Exactly how does an atom of p differ from p3·7 f 30-.j - V)( e 'M. C,f-rbf\ + n_ ° ? h e ore e If s �ts ((,muJ 13. Given a neutral iron atom (Fe), what must be done in order to make it into a Fe 2+ cation? Average atomic mass 14. The element X consists of three isotopes 10x (25%), 11X (65%), and 12X (10%). a. Calculate the average atomic mass (using correct units!) (, 2 5 xl D) � ( (o$" > ).:___ . __ _ \ \ l, Vi ' k" lo ()J'Yl LA- 2. Calculate the average atomic mass of lithium, which occurs as two isotopes that have the following atomic masses and abundances in nature: 6 amu, 7.30% and 7 amu, 92.70%. (.073 � G,) + (,92,. 7 X f) -= 1�9 .- 21 -0,.,VY\ \A \ --- - 3. Hydrogen is 99% 1 H, 0.8% 2 H, and 0.2% 3 H. Calculate its average atomic mass. 4. Calculate the average atomic mass of magnesium using the following data for three magnesium isotopes. Isotope mass(u) relative abundance Mg-24 23.985 0.7870 Mg-25 24.986 0.1013 Mg-26 25.983 0.1117 c 1g7 x 2 3 . q ts ') ¥ ( • 1 o 13 x 2L4. °1 �to) � (., 1 17 x 2� . 9 f 3 ') ft:L3!�� I 5. Calculate the average atomic mass of iridium using the following data for two iridium isoto�-;------. Isotope mass (u) relative abundance lr-191 191.0 0.3758 lr-193 193.0 0.6242 6. Lithium has two naturally occurring isotopes: lithium-6 and lithium-?. If the average atomic mass of lithium is6.941 amu, which isotope is the most abundant? How do you know? 1 7 --rhOvV'\ lo \