Chapter 8 Regular Home Work Chemistry 121

• Give the number of unpaired electrons present in a ground-state atom of Fe.

            Answer:  4

• Give the number of unpaired electrons present in a ground-state atom of S.

            Answer: 2

• Give the number of unpaired electrons present in a ground-state atom of Tl.

            Answer: 1

• Give the number of unpaired electrons present in a ground-state atom of Cr.

            Answer: 6

• Give the number of unpaired electrons present in a ground-state atom of Fe²⁺.

            Answer: 4

• Give the number of unpaired electrons present in a ground-state of the ion formed when one electron is ionized from an O atom.

            Answer: 3

• Give the number of unpaired electrons present in a ground-state atom of Se^2-.

            Answer: 0

• Give the number of unpaired electrons present in a ground-state atom of Al³⁺.

            Answer: 0

• Using the abbreviated notation, the ground-state electron configuration of Y³⁺ is

            Answer:  [Kr]  -- Is the correct answer. 

                          Y losses three electron to become Y+ and attains the electronic configuration of Kr. 

• Using the abbreviated notation, the ground-state electron configuration of Br^- is

            Answer: [Kr] -- Br gains an electron to become Br-. Therefore, it has same electronic                                  configuration as Kr

• Using the abbreviated notation, the ground-state electron configuration of Rh²⁺ is

            Answer: [Kr] 4d^{7 -- The electronic configuration of Rh is [Kr] 5s2 4d7. it looses 2 electron                                    from outer orbital that is 5s. why? because n = 5 is outer orbital comes before 4d}

• Using only a periodic table as a guide, arrange each of the following series of atoms in order of increasing size.

            Answer: a. Be, Li, Na 

                            b. Be, Na, Li

                            c. Na, Be, Li

                            d. Na, Li, Be

                            e. Li, Na, Be

                            f. Li, Be, Na

• Using only a periodic table as a guide, arrange each of the following series of atoms in order of increasing size.

            Answer: a. F, N, P 

                            b. F, P, N

                           c. P, F, N

                           d. P, N, F

                           e. N, P, F

                           f. N, F, P

                          Note:  Please refer to the above Image for getting correct answer

• Using only a periodic table as a guide, arrange each of the following series of atoms in order of increasing size.

            Answer: a. O, I, Sn 

                           b. O, Sn, I

                           c. Sn, I, O

                           d. Sn, O, I

                           e. I, Sn, O

                           f. I, O, Sn

                          Note:  Please refer to the above Image for getting correct answer

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing size.

            Answer: a. O^2-, F, F^-

                           b. O^2-, F^-, F

                           c. F^-, F, O^2-

                           d. F^-, O^2-, F

                           e. F, O^2-, F^-

                           f. F, F^-, O^2- 

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing size.

            Answer: a. Al³⁺, Mg, Na 

                          b. Al³⁺, Na, Mg

                          c. Na, Al³⁺, Mg

                          d. Na, Mg, Al³⁺

                          e. Mg, Na, Al³⁺

                          f. Mg, Al³⁺, Na

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing size.

            Answer: a. N, P, Si 

                           b. N, Si, P

                           c. Si, N, P

                           d. Si, P, N

                           e. P, Si, N

                           f. P, N, Si

• Indicate which species in each pair has the higher ionization energy.

            Answer: Select one or more:

                          a. Between K and I, I 

                          b. Between K and I, K

                          c. Between Al and Al⁺, Al

                          d. Between Al and Al⁺, Al⁺ 

                          e. Between Ar and Cl^-, Ar 

                          f. Between Ar and Cl^-, Cl^-

                          g. Between Mg and Ca, Mg 

                          h. Between Mg and Ca, Ca

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing first ionization energy.

            Answer: a. K, Se, S 

                           b. K, S, Se

                           c. S, K, Se

                           d. S, Se, K

                           e. Se, K, S

                           f. Se, S, K

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing first ionization energy.

            Answer: a. Cr, As, O 

                           b. Cr, O, As

                           c. O, Cr, As

                           d. O, As, Cr

                           e. As, Cr, O

                           f. As, O, Cr

• Using only a periodic table as a guide, arrange each of the following series of species in order of increasing first ionization energy.

            Answer: a. O, O^-, F

                           b. O, F, O^-

                           c. F, O, O^-

                           d. F, O^-, O

                           e. O^-, F, O

                           f. O^-, O, F 

• Which electron configuration represents the most highly excited state of C?

            Answer: a. 1s²2s²2px¹2py¹

                           b. 1s²2s²2px²

                           c. 1s²2s¹2px¹2py¹2pz¹

                           d. 1s¹2s²2px¹2py¹2pz¹    

                           The Word is Most Excited Stated . In most excited state the inner electron jumps out 

                           the S orbital and moves to P orbital to make it half-filled  P orbital.

• Write the electron configuration of the copper atom and the 2⁺ cation of copper. Check the correct choices.

            Answer: a. Cu [Ar] 4s²3d⁹

                           b. Cu [Ar] 4s¹3d¹⁰ 

                           c. Cu [Ar] 4s⁰3d¹¹

                           d. Cu²⁺ [Ar] 4s²3d⁹

                           e. Cu²⁺ [Ar] 4s⁰3d⁹ 

                           f. Cu²⁺ [Ar] 4s²3d⁷

• Which ground-state electron configuration represents the element with the largest size?

            Answer: a. 1s²2s²2p¹ 

                           b. 1s²2s²2p⁴

                           c. 1s²2s²2p⁵

                           d. 1s²2s²2p³

                           Note: Refer to Atomic Radius Trend 

• Which ground-state electron configuration represents the element with the smallest ionization energy?

            Answer: a. 1s²2s²2p¹ 

                           b. 1s²2s²2p⁴

                           c. 1s²2s²2p⁵

                           d. 1s²2s²2p³

• Which ground-state electron configuration represents the element with the most negative electron affinity?

            Answer: a. 1s²2s²2p¹

                           b. 1s²2s²2p⁴

                           c. 1s²2s²2p⁵ 

                           d. 1s²2s²2p³

• Arrange the elements lithium, carbon, and oxygen in order of increasing size.

            Answer:  a. O, C, Li 

b. O, Li, C

c. C, Li, O

d. C, O, Li

e. Li, C, O

f. Li, O, C

• Arrange the elements lithium, carbon, and oxygen in order of increasing first ionization energy.

            Answer: a. O, C, Li

                           b. O, Li, C

                           c. C, Li, O

                           d. C, O, Li

                           e. Li, C, O 

                           f. Li, O, C

• Arrange the elements lithium, carbon, and oxygen in order of increasing second ionization energy.

            Answer: a. O, C, Li

                           b. O, Li, C

                           c. C, Li, O

                           d. C, O, Li 

                           e. Li, C, O

                           f. Li, O, C

• Arrange the elements lithium, carbon, and oxygen in order of increasing number of unpaired electrons. (There are two correct choices since 2 have the same number.)

            Answer: a. O, C, Li

                           b. O, Li, C

                           c. C, Li, O

                           d. C, O, Li

                           e. Li, C, O 

                           f. Li, O, C 

• In the reaction of lithium with oxygen, what expected compound is formed? If the compound is written Li_xO_y, what is x+y? For example, water is H₂O. In this case x =2, y = 1, and you write 3 in the space provided for the answer.

            Answer: 3

• Write the equation for the reaction, if any, of lithium with nitrogen. If there is a reaction forming Li_xN_y, what is x+y?

            Answer: 4

• Write the equation for the reaction, if any, of lithium with water. What products are formed?

            Answer: a. No reaction

                           b. H₂ gas 

                           c. O₂ gas

                           d. Li⁺(aq) 

                           e. OH^-(aq) 

                           f. H⁺(aq)

• Write the electron configuration of the alkali metal (M) that reacts with oxygen to yield an oxide, M₂O, if 1.22 g of the metal reacts with 1.41 g of oxygen to form 2.63 g of the oxide.

            Answer:  a. [He] 2s¹ 

                           b. [Ne] 3s¹

                           c. [Ar] 4s¹

                           d. [Kr] 5s¹

                           e. [Xe] 6s¹

• In the reaction of iron and chlorine, what mass of iron is needed to prepare 16.29 g of the iron chloride product if, under the conditions of the reaction, the electron configuration of the iron cation in the product is 1s²2s²2p⁶3s²3p⁶3d⁶?

            Answer: 7.18g 

                           How to : (16.29 g fecl2 ) * (1 mol fecl2 / 126.751g fecl2) = 0.1285 moles of fecl2 

                           0.1285Moles of fecl2 * 55. 85 grams of fe = 7.18g

• Which of the following reactions produce H₂ gas?

            Answer: a. Na(s) + cold water 

                           b. NaH + cold water 

                           c. Na₂O + cold water

                           d. Mg + cold water

                           e. Ni + cold water

• Which of the following reactions produce a basic solution (the hydroxide ion)?

            Answer: a. Na(s) + cold water 

                           b. NaH + cold water 

                           c. Na₂O + cold water

                           d. Mg + cold water

                           e. Ni + cold water

• Which of the following reactions produces iron, the metal?

            Answer: a. FeCl₃(aq) + Zn(s) 

                           b. FeCl₃(aq) + Cu(s)

                           c. FeCl₃(aq) + Ca(NO₃)₂(aq)

                           d. FeCl₃(aq) + Br₂(l)

                           e. FeCl₃(aq) + F₂(g)

• Which of the following reactions produces chlorine gas?

            Answer: a. FeCl₃(aq) + Zn(s) 

                           b. FeCl₃(aq) + Cu(s)

                           c. FeCl₃(aq) + Ca(NO₃)₂(aq)

                           d. FeCl₃(aq) + Br₂(l)

                           e. FeCl₃(aq) + F₂(g)

• Match oxides with correct property. 

            Answer: 

CaO	Answer 1Choose...BasicAcidicAmphoteric
K2O	Answer 2Choose...BasicAcidicAmphoteric
CO2	Answer 3Choose...BasicAcidicAmphoteric
N2O5	Answer 4Choose...BasicAcidicAmphoteric
Al2O3	Answer 5Choose...BasicAcidicAmphoteric

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