Curso de reforzamiento 10th grado II trimester Cortesia de Taipan

Consider the series 2 8 18 32 found in atomic electron configurations. a) What is the next number in the series? __________ b) Divide each number in the series by two. What does the new resulting series imply about the electron configuration of the atom?

-------------------------------------A certain 3+ ion has the orbital diagram: Identify the ion _________. 1s 2s 2px 2py 2pz----------------------------------------------------------

How many unpaired electrons are in manganese (Mn)? __________________.

Shown below are the ionization energies for three elements in the thirdperiod. Label each box with the correct groupI1 I2 I3 I4496 4560 6912 9543737 1451 7733 10,540578 1816 2744 11,577----------------------------------------------The first four ionization energies for element X and Y (not in kJ/mol) are 170, 350, 1800, 2500. X 200, 400, 3500 5000. Y

Write the possible formulas for X and Y. More than one formula is possible.

Which of the following has the largest I2? (Transition metals lose their selectrons before the d electrons) K Ca Sc Fe

For each of the following pairs, which of the two species is larger?a) N3- or F- b) Mg2+ or Ca2+ c) Fe2+ or Fe3+

How many electrons are present in the 77Se2- ion? (a) 32 (b) 34 (c) 43 (d) 77 (e) none of these

Calculate the number of electrons on a Ce4+ ion if the atomic number of this element is 58 and the mass of the ion is 140 amu. (a) 54 (b) 58 (c) 62 (d) 136 (e) 140

Which has the largest charge to mass ratio:(a) a proton (b) a neutron (c) an -particle(d) an electron (e) an x-ray

Which of the following would have the largest I1? Na K Li Cs

Shown below are I1 (in kJ/mol) values for sequential elements in period 3.Assign elements to these values based on the trends discussed above.740 578 786 1012 999

What would you describe as the key result of the Rutherford experiment, in which a metal target was bombarded with -particles? (a) The -particles were able to pass through the target. (b) The particles were found to knock electrons out of the target. (c) Some of the -particles were deflected through large angles. (d) Flashes of light were emitted when the -particles hit the ZnS screen after they passed through the target. (e) The experiment showed the need for better -particle detectors----------------------------------What is the difference between 14C and 14N atoms?---------------------------------

How many electrons, protons, and neutrons could be found in an 56Fe3+ ion formed during a supernova explosion?

Electromagnetic Radiation3-13. What is the wavelength in centimeters of light that has a frequency of 2.33 x 1015 s-1? (a) 6.99 x 1025 cm (b) 7.77 x 104 cm (c) 1290 cm (d) 1.29 x 10-5 cm (e) none of the above

3-14. A helium-neon laser emits light with a wavelength of 6328 . What is the energy of a 6328 photon in joules? (a) 2.179 x 10-19 J (b) 3.139 x 10-19 J (c) 5.448 x 10-19 J (d) 6.328 x 10-19 J (e) 2.179 x 10-18 J

3-15. If green light has a frequency of 5.0 x 1014 s-1 what is the wavelength (in meters) of this light? (a) 6.7 x 10-24 (b) 2.0 x 10-15 (c) 6.0 x 10-7 (d) 3.0 x 108 (e) none of the above

3-16. If x-rays have a shorter wavelength than ultraviolet-rays, which of the following statements is true? (a) x-rays have smaller frequencies than UV-rays. (b) x-rays travel faster than UV-rays. (c) x-rays have more energy than UV-rays. (d) x-rays have a larger amplitude than UV-rays. (e) none of the above statements are true.

3-22. A cheap spectrophotometer can be made using a light-emitting diode as the source of the light. Assume that you build one of these spectrometers using an LED that gives off green light with a wavelength of 520 nm. What is the energy of a photon of this green light?(a) 1.15 x 10-34 J (b) 1.03 x 10-22 J (c) 3.82 x 10-21 J (d) 3.82 x 10-19 J (e) none of the aboveAnswer: (d)

3-23. In what portion of the electromagnetic spectrum are you likely to find the radiation that carries just enough energy to be dangerous to life because it can ionize the water that is so important to living organisms?(a) Radio/TV waves, 10 - 0.1 m (b) Microwaves, 0.01 - 10-4 m(c) Ultraviolet, 10-7 - 10-9 (d) X-rays, 10-10 - 10-12 m(e) -rays, 10-12 - 10-14 m Answer: (c)

Which of the following transitions in the spectrum of the hydrogen atom results in the absorption of a photon with the largest energy? (a) n = 2 to n = 3 (b) n = 2 to n = 4 (c) n = 1 to n = 4 (d) n = 3 to n = 1 (e) n = 7 to n = 1 Answer: (c)Which transition in the spectrum of the hydrogen atom results in the emission of light with the longest wavelength? (a) n = 3 to n = 2 (b) n = 3 to n = 1 (c) n = 5 to n = 4 (d) n = 2 to n = 3 (e) n = 1 to n = 3 Answer: (c)

What is the energy of the light emitted when an electron falls from the n = 4 to the n = 2 orbit in the hydrogen atom? (a) 4.09 x 10-19 J (b) 5.45 x 10-18 J (c) 4.36 x 10-18 J (d) 2.62 x 10-17 J Answer: (a)

Which ONE of the following atoms (electron configurations shown below) should have the most negative value for the ELECTRON AFFINITY of the free atom? Atoms are designated by electronic configuration. [DISCUSSDEFINITION OF ELECTRON AFFINITY first: M + e M-, trends for EA and WHICH GROUP THISELEMENT IS LIKELY TO BE IN if EA is very negative, i.e. when formation of anion is favorable ]!!!a. 1s2 2s2 2p6 3s1 (Na) b. 1s2 2s2 2p5 (F)c. 1s2 2s2 2p6 3s2 3p2 (Si) d. 1s2 2s2 2p6 3s2 3p6 3d5 4s2 (Mn)e. 1s2 2s2 2p6 (Ne)Which of the following properties, in general, increase as we move left to right across a period in the periodic table?1. atomic radius 2. ionization energy 3. metallic character

a. 1 only b. 2 only c. 3 only d. 1 and 2 only

Which of the following atoms has the most negative electron affinity (EA)?a. Na b. Cl c. Br d. S e. As

Consider the ions of S2, O 2- F, Na+, Mg2+. Order the ions with ionic radius from largest to smallest? a. S2 , O2- , F, Na+, Mg2+

Para el in Cl (Z=17) del istopo cuyo nmero msico es 36:a) Indique el nmero de protones, electrones y neutrones.b) Escriba su configuracin electrnica.c) Indique los valores de los nmeros cunticos de uno de los electrones externos.

Para un elemento de nmero atmico Z = 20, a partir de su configuracin electrnica:a) Indique el grupo y el periodo al que pertenece y nombre otro elemento del mismo grupo.b) Justifique la valencia ms probable de ese elemento.c) Indique el valor de los nmeros cunticos del electrn ms externo.

Dados los conjuntos de nmeros cunticos: (2,1,2, ); (3,1,1, ); (2,2,1,); (3,2,2, )a) Razone cules no son permitidos. (2,1,2, ); (2,2,1,);Indique en qu tipo de orbital se situara cada uno de los electrones permitidos.(3,1,1, ) (3,2,2, )Dadas las especies qumicas Ne y O2, razone la veracidad o falsedad de las siguientes afirmaciones:a) Ambas especies poseen el mismo nmero de electronesb) Ambas especies poseen el mismo nmero de protones.c) El radio del ion xido es mayor que el del tomo de nen. VERDADERO.El nmero de protones en los ncleos de cinco tomos es el siguiente: A = 9; B = 16; C = 17; D = 19; E = 20 Razone: a) Cul es el ms electronegativo? b) Cul posee menor energa de ionizacin? c) Cul puede convertirse en anin divalente estable?A (9) 1s2 2s2 2p5 B (16) 1s22s22p63s23p4C (17) 1s22s22p63s23p5 D (19) 1s22s22p63s23p64s1 E (20) 1s22s22p63s23p64s2

Escriba las configuraciones electrnicas de las especies siguientes: N3 (Z = 7), Mg2+ (Z = 12), Cl (Z = 17), K (Z = 19) y Ar (Z = 18). Indique los que son isoelectrnicos. Indique los que presentan electrones desapareados y el nmero de los mismos.

La configuracin electrnica de un elemento A termina en 3d10 4p2a) Justifique si se trata de un metal o un no metal.A que grupo pertenece _________Cual es el elemento ___________Que ion podra formar _____________Cual seria la energa de ionizacin donde se obtendra el salto mas alto o diferencia mas alta._________

La configuracin electrnica del ion X3+ es 1s22s22p63s23p6.a) Cul es el nmero atmico y el smbolo de X?b) A qu grupo y periodo pertenece ese elemento?c) Razone si posee electrones desapareados el elemento X.

Dadas las configuraciones electrnicas:A : 1s23s1 ; B : 1s22s3 ; C : 1s22s22p63s23p5; D : 1s22s22px22py02pz0Indique razonadamente:a) La que no cumple el principio de exclusin de Pauli.b) La que no cumple el principio de mxima multiplicidad de Hund.c) La que, siendo permitida, contiene electrones desapareados.

Razone si para un electrn son posibles las siguientes series de nmeros cunticos: (0, 0, 0, -1/2); (1, 1, 0, +1/2); (2, 1, -1, +1/2); (3, 2, 1, -1/2).b) Indique a qu tipo de orbital corresponden los estados anteriores que sean posibles.c) Indique en cul de ellos la energa es mayor.------------------------------------------------------------A partir de los tomos A y B cuyas configuraciones electrnicas son, respectivamente, 1s22s2 y 1s2 2s2 2p6 3s2 3p5a) Explique la posible existencia de las molculas: AB2, B2 y AB4

Razone si las siguientes configuraciones electrnicas son posibles en un estado fundamental o en un estado excitado: a) 1s2 2s2 2p4 3s1. b) 1s2 2s2 2p6 3s2 3p1. c) 1s2 2s2 2p6 2d10 3s2

Dadas las siguientes configuraciones electrnicas de la capa de valencia:

a) Indique el grupo al que corresponde cada una de ellas.b) Nombre dos elementos de cada uno de los grupos anteriores.1) ns1 2) ns2 np4 3) ns2 np6

----------------------------------------------------------------

1 E.I.2 E.I.3 E.I.4 E.I

Li521729411819-----

Na492456469379561

K415306844485895

En la tabla siguiente se dan las energas de ionizacin (kJ/mol) de los primeros elementos alcalinos. Explique:1. Por qu disminuye la 1 E.I. del Li al K?2. Por qu no hay valor para la 4 E.I. del Li?3. Por qu aumenta de la 1 E.I. a la 4 E.I.?

ElementosNa?Al?S?

Radios atmicos?136?110?99

Considere la siguiente tabla incompleta:

Reproduzca la tabla y compltela situando los valores 125 nm, 104 nm y 157 nm

True or false and why(a) The first ionization energy of oxygen (1314 kJ mol) is greater than the first ionizationenergy of sulfur (999.5 kJ mol)

(b) The first ionization energy of beryllium (899 kJ mol) is greater than the first ionizationenergy of lithium (520 kJ mol).

(c) The first ionization energy of helium (2373 kJ mol) is much greater than the firstionization energy of lithium (520 kJ mol).

(d) The fourth ionization energy of boron (25,000 kJ mol) is much greater than the fourthionization energy of carbon (6220 kJ mol).

(e) The atomic radius of argon (98 pm) is larger than the atomic radius of neon (70 pm).

(f) The atomic radius of aluminum (143 pm) is larger than the atomic radius of silicon (132pm).(g) The first ionization energy of aluminum (577.9 kJ mol) is less than the first ionizationenergy of magnesium (738.1 kJ mol).

(h) The first ionization energy of sulfur (999.5 kJ mol) is less than the first ionization energyof phosphorus (1012 kJ mol).

(i) The ionic radius of the calcium ion, Ca2+, (99 pm) is smaller than the atomic radius of thecalcium atom (197 pm).

(j) The ionic radius of the sulfide ion, S2-, (184 pm) is larger than the atomic radius of thesulfur atom (127 pm).

(k) Determine which of the following species are isoelectronic with neon: Mg2+, Cl, Kr, N3-, K+.

(l) The ionic radius of the oxide ion, O2-, (140 pm) is larger than the ionic radius of thealuminum ion, Al3+, (50 pm).

(m) The first ionization energy of neon (2080 kJ mol) is greater than the first nation energyof the fluoride ion, F (333 kJ mol) but less than the first ionization energy of the sodiumion, Na+, (4560 kJ mol).

(n) Sodium reacts vigorously with non-metals to form ionic compounds containing the Na+ ion.No ionic compound containing the Na2+ ion exists.

(o) Potassium is more reactive than calcium but less reactive than cesium in all respects. (Hint:these metals react with non-metals to form cations).

(p) The electron affinities of the halogens are very exothermic.Answer (a) same family, Zeff of valence electron removed about the same. I1 decreases with n-valueas an electron in shell further from nucleus is easier to remove.(b) same period, n(constant). Zeff Be > Zeff Li (period trend)(c) ls electrons of He are poorly screened from nucleus. They are very close to nucleus andstrongly held. The 2s electron of Lithium is well screened by its core electrons, is in a shellfurther from the nucleus and it is weakly held.(d) A strongly held core electron is removed from B vs well screened valence electronremoved from C.(e) same family, argon has one more electron shell.(f) same period, n(constant). Zeff Si > Zeff Al (period trend)(g) same period, 3p electron of Al does not penetrate inner shells as well as 3s electron ofMg. It feels a lower Zeff and a weaker nuclear attraction.(h) same period, paired electron removed from oxygen experiences greater repulsions dueto close proximity of electrons in same orbital vs the unpaired electron removed fromnitrogen. This lowers its Zeff and the nuclear attraction for it.(i) Ca2+ has only 3 electron shells occupied vs 4 for Ca.(j) S2- has extra 2 electrons. They increase repulsions and decrease Zeff of the valenceelectrons. The electrons are not held as tightly and they spread out.(k) Mg2+, N3(l) isoelectronic species: Al3+ has more protons (13) vs O2- which has only 8. A larger #protons means a greater nuclear attraction pulling the electrons in closer.(m) isoelectronic species: Na+ has the most protons (11) and the greatest nuclear attractionto overcome. F has the least protons (9) and the weakest nuclear attraction toovercome.(n) weak nuclear attraction for well screened valence 3s electron. Very strong nuclearattraction for core 2p electrons(o) metals react to form K+, Ca2+, Cs+ ions. I1(Cs) < I1 (K) < (I1 + I2) (Ca). Reactivitywould increase as the energy required in the reaction to form the product cation decreasesmaking Cs most reactive and Ca least reactive.(p) The effective nuclear charge on the valence np electrons of a halogen is quite large so thenuclear attraction for the added electron is relatively strong. Also, a filled np subshell anda noble gas electron configuration results which is very stable.

Dadas las siguientes especies: Ar, Ca2+ y Cl- .a) Escriba sus configuraciones electrnicas.b) Ordnelas, razonando la respuesta, en orden creciente de sus radios.Nmeros atmicos: Ar = 18; Ca = 20; Cl = 17Razone qu grfica puede representar:a) El nmero de electrones de las especies: Ne, Na+, Mg2+ y Al3+.b) El radio atmico de los elementos: F, Cl, Br y I.c) La energa de ionizacin de: Li, Na, K y Rb.

3-30. If a laser operated on the n = 5 to n = 2 transition of a H atom, what wavelength photon would be emitted? (a) 380 nm (b) 434 nm (c) 1950 nm (d) 3910 nm (e) none of the above Answer: (b)

Quantum Numbers

3-31. Which of the following quantum numbers is used to describe the orientation of an orbital in space? (a) n (b) l (c) m (d) s (e) none of these quantum numbers describe the orientation of an orbital in space. Answer: (c)

3-32. Which of the following quantum numbers can have a value that is not an integer? (a) n (b) l (c) m (d) s (e) none of the quantum numbers can have any value that is not an integer Answer: (d)

3-33. What kind of orbital is described by the quantum numbers: n = 4, l = 2, m = -1?(a) 4s (b) 4p (c) 4d (d) 4f (e) none of these Answer: (c)

3-34. Orbitals for which l = 1 are described by which of the following symbols? (a) s (b) p (c) d (d) f (e) g Answer: (b)

3-35. The Pauli exclusion principle states that: (a) No two electrons in an atom can have the same spin. (b) No two electrons in an atom can occupy the same orbital. (c) Two electrons in the same orbital have identical values of the spin quantum number. (d) No two electrons in an atom can have the same set of four quantum numbers. (e) No two electrons in an atom can have the same principal quantum number. Answer: (d)

3-36. In the absence of an external magnetic field, the energy of an electron in an orbital in a lithium atom is determined by which pair of quantum numbers? (a) n and l (b) n and m (c) n and s (d) l and m (e) m and s Answer: (a)

3-37. Two orbitals are said to be degenerate if they: (a) Contain the same number of electrons (b) Have the same value for the angular quantum number, l, and different values of the principal quantum-number, n (c) Have the same set of three quantum numbers, n, and m, but have different values of the s quantum number (d) Have the same energy (e) Contain the same number of unpaired electrons Answer: (d)

3-38. What is the maximum number of electrons that can be accommodated in the subshell for which n = 3 and l = 2? (a) 2 (b) 6 (c) 10 (d) 14 (e) 18Answer: (c)3-39. Calculate the maximum number of electrons that can fit into the n = 4 shell of orbitals. (a) 6 (b) 8 (c) 18 (d) 16 (e) 32 Answer: (e)

3-40. Which of the following selection rules for quantum numbers is incorrectly stated? (a) n is any integer greater than or equal to zero. (b) l is any integer between zero and n - l. (c) m is any integer between -l and +l. (d) s is either + or -. (e) All of the above selection rules are correctly stated.Answer: (a)

3-41. Which of the following atomic orbitals doesnt exist? (a) 3f (b) 3p (c) 5f (d) 5d (e) 6s Answer: (a)

3-42. Which is a legitimate set of n, l, m and s quantum numbers? (a) 0,0,0, (b) 8,4,-3,- (c) 3,3,2,+ (d) 2,1,-2,- (e) 5,3,3,-1 Answer: (b)

3-43. Which set of n, l, m and s quantum numbers is allowed?(a) 4,-2,-1, (b) 4,2,3, (c) 4,3,0,1 (d) 4,0,0,- Answer: (d)

3-44. Which of the following sets of n, l, m and s quantum numbers isnt allowed? (a) 1,1,0,+ (b) 2,0,0,+ (c) 3,2,1,- (d) 4,1,-1,+ (e) 5,3,2,- Answer: (a)

3-45. Which set of quantum numbers can be used to describe a 2p electron? (a) 2,1,0,- (b) 2,0,0, (c) 2,2,1, (d) 3,2,1,- (e) 3,1,0, Answer: (a)

3-46. How many electrons can be placed in a 3d orbital? (a) 2 (b) 6 (c) 8 (d) 10 (e) 18 Answer: (a)

3-47. What is the maximum number of unpaired electrons that can be accommodated in a 5d subshell? (a) 3 (b) 5 (c) 6 (d) 7 (e) 10Answer: (b)

3-48. When Schrdingers wave mechanics model is applied to an isolated atom in the gas phase, the energy of an electron in an orbital on the atom is determined by which pair of quantum numbers?(a) n and l (b) n and m (c) n and s (d) l and m (e) m and s Answer: (a)

Aufbau Principle

3-49. Which of the following is an incorrect order of increasing energy of the atomic orbitals?(a) 3s < 4s < 5s (b) 5s < 5p < 5d (c) 5s < 4d < 5p (d) 5p < 6s < 4f (e) None of these are incorrect Answer: (e)

3-50. Which set of orbitals is arranged in increasing order of energy? (a) 3d < 4s < 4p < 5s < 4d (b) 3d < 4s < 4p < 4d < 5s (c) 4s < 3d < 4p < 5s < 4d (d) 4s < 3d < 4p < 4d < 5s (e) 3d < 4s < 4p < 4d < 5s Answer: (c)

3-51. Which of the following sets of atomic orbitals are degenerate for a lithium atom? (a) 3s, 3px, 3dz2 (b) 2px, 2py, 2pz (c) 2px, 3px, 4px (d) None of these sets of orbitals are degenerate. (e) All of these sets of orbitals are degenerate. Answer: (b)

3-52. When atomic orbitals are filled according to the Aufbau principle, the 6p orbitals are filled immediately after the: (a) 4f (b) 5d (c) 6s (d) 7s orbitals Answer: (b)

3-53. Which of the following subshells of orbitals is filled first when electrons are added to the atomic orbitals on a xenon atom? (a) 4d (b) 4f (c) 5s (d) 5p (e) 5d Answer: (c)

3-54. Which of the following orbitals would be filled first when electrons are added to a gold atom? (a) 4f (b) 5d (c) 6s (d) 6p (e) 6d Answer: (c)

3-55. In what group of the periodic table would an element with the following electron configuration belong? 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 (a) Group IA (b) Group IlIA (c) Group VA (d) Group VIIA (e) none of the aboveAnswer: (b)

3-56. A single atom of element 109 has been synthesized. Use the Aufbau principle to predict the electronic configuration of this element. Which of the following elements would 109 most resemble? (a) Ta (b) Re (c) Ir (d) Au (e) Tl Answer: (c)

3-57. A single atom of element 114 was recently synthesized. Use the Aufbau principle to predict the electronic configuration of this element. Which of the following elements would 114 most resemble? (a) Au (b) Hg (c) Tl (d) Pb (e) Po Answer: (d)

3-58. Theoreticians predict that the element with atomic number 120 will be more stable than the elements recently discovered with atomic numbers between 103 and 109. On the basis of the Aufbau principle, and the order of filling of atomic orbitals, the chemistry of this element should most closely resemble the chemistry of which of the following? (a) Ra, Group IIA (b) Pb, Group IVA (c) Po, Group VIA (d) Rn in Group VIIIA (e) One of the transition metals between La and Hg Answer: (a)

3-59. In row 6 of the Periodic table, the series of elements which differ in the number of electrons contained in f orbitals: (a) begins with Cs and ends with Rn (b) begins with La and ends with Hg (c) begins with Tl and ends with Rn (d) begins with La and ends with Rn (e) begins with Ce and ends with Lu.Answer: (b)

3-60. Which neutral atom has the most unpaired electrons? (a) Na (b) Al (c) Si (d) P (e) S Answer: (d)

3-61. Which atom contains the largest number of unpaired electrons? (a) B (b) N (c) F (d) Ti (e) Cu Answer: (b)

3-62. Which atom or ion has the largest number of unpaired electrons? (a) Li+ (b) B (c) C4- (d) N (e) O2-Answer: (d)

3-63. Which element has the largest number of electrons for which the angular quantum number is equal to 1? (a) He (b) F (c) S (d) As (e) Zn Answer: (d)

3-64. A possible set of quantum numbers for the last electron added to form a gallium atom (Z = 31) in its ground state is: (a) 3, 1, 0, - (b) 3, 2, 1, (c) 4, 0, 0, (d) 4, 1, 1, (e) 4, 2, 2, Answer: (d)

3-65. A possible set of quantum numbers for the last electron added to form an As3+ ion is: (a) 3, 1, -1, (b) 4, 0, 0, - (c) 3, 2, 0, (d) 4, 1, -1, (e) 5, 0, 0, Answer: (c)

3-66. The outermost or highest energy electron in element 105 could be characterized by which of the following sets of n, l, m and s quantum numbers? (a) 7, 3, -3, - (b) 6, 3, -1, - (c) 6, 2, 0, (d) 5, 3, -1, - Answer: (c)

3-67. Which of the following describes a possible set of quantum numbers for the last electron added to form an aluminum atom when atomic orbitals are filled? (a) 1, 0, 0, + (b) 2, 0, 0, + (c) 2, l, 1, + (d) 3, 0, 0, + (e) 3, 1, 1, +Answer: (e)

3-68. Which of the following sets of n, l, m and s quantum numbers could describe the electron removed from a neutral Al atom when the first ionization energy of aluminum is measured? (a) 1, 0, 0, + (b) 2, 0, 0, + (c) 2, 1, 1, + (d) 3, 0, 0, + (e) 3, 1, l, +Answer: (e)

Electron Configurations

3-69. An element with the electron configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 5s2 4d10 5p3 would belong in which group or family of the periodic table? (a) Group IA (b) Group IIIA (c) Group IVA (d) Group VA (e) Group VIIA Answer: (d)

3-70. Which electron configuration for carbon would satisfy Hund's rules? (a) 1s2 2s2 2px2 2py0 2pz0 (b) 1s2 2s2 2px1 2py1 2pz0 (c) 1s2 2s2 2px1 2py1 2pz1 (d) 1s2 2s2 2px2 2py1 2pz1(e) none of these configurations satisfy Hund's rules.Answer: (b)

3-71. What is the ground state electronic configuration of a fluorine atom? (a) 1s2 2s2 2p5 (b) 1s2 2s2 2p6 (c) 1s2 2s2 2p7 (d) 1s2 2s2 2p6 3s1 (e) none of the aboveAnswer: (a)

3-72. What is the value of x in the following electron configuration for silicon?1s2 2s2 2p6 3s2 3px(a) 1 (b) 2 (c) 3 (d) 4 (e) 6Answer: (b)

3-73. What is the correct electron configuration for the Ti atom? (a) 1s2 2s2 2p6 3s2 3p6 3d4(b) [Ar] 4s2 4d2 (c) [Ar] 4d4 (d) 1s2 2s2 2p6 3s2 3d2 (e) [Ar] 4s2 3d2Answer: (e)

3-74. Which of the following would have the electron configuration: 1s2 2s2 2p6 3s2 3p6 3d4 (a) Ca2+ (b) Cr2+ (c) Fe2+ (d) Ti2+ (e) none of theseAnswer: (b)

3-75. What is the correct electron configuration for the P3+ ion? (a) [Ne] (b) [Ne] 3s2 (c) [Ne] 3s2 3p3 (d) [Ne] 3s2 3p6Answer: (b)

3-76. What is the electron configuration for the bromide ion, Br-? (a) [Ar] 4s2 4p5 (b) [Ar] 4s2 3d10 4p7 (c) [Ar] 4s2 3d10 4p5 (d) [Ar] 4s2 3d10 4p6 (e) [Ar] 4s2 3d10 3p6 Answer: (d)

3-77. Which of the following describes the electron configuration for the Sn2+ ion? (a) [Kr] 4d10 (b) [Kr] 5s2 (c) [Kr] 5s2 5p2 (d) [Kr] 5s2 4d10 (e) [Kr] 5s2 4d10 5p2 Answer: (d)

3-78. What is the electronic configuration of the Alx+ ion in the ionic compound Al2O3? (a) 1s2 2s2 2p6 (b) 1s2 2s2 2p6 3s2 (c) 1s2 2s2 2p6 3s2 3p1 (d) 1s2 2s2 2p6 3s2 3p4 (e)1s2 2s2 2p6 3s2 3p6 Answer: (a)

3-79. If the X2- ion has no unpaired electrons, in what Group does element X belong? (a) IA (b) IIA (c) IVA (d) VIA (e) VIIAAnswer: (d)