1.67 Which of the following statements are true for many-electron atoms? If false, explain why. (a) The effective nuclear charge Zeff is independent of the number of electrons present in an atom. (b) Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbital can penetrate to the nucleus of the atom. (c) Electrons havingl = 2 are better at shielding than electrons havingl = 1. (d) Zeff for an electron in a p-orbital is lower than for an electron in an s-orbital in the same shell

1.67 Which of the following statements are true for many-electron atoms? If false, explain why. (a) The effective nuclear charge Zeff is independent of the number of electrons present in an atom. (b) Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons from the nuclear charge because an electron in an s-orbital can penetrate to the nucleus of the atom. (c) Electrons havingl = 2 are better at shielding than electrons havingl = 1. (d) Zeff for an electron in a p-orbital is lower than for an electron in an s-orbital in the same shell

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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7. Transition elements come from the d block. Examples of d block elements are manganese, cobalt, iron, copper, scandium and zinc. (a) Write the electron configurations for the atoms and ions of manganese and cobalt below. Mn atom: 1s? Co2* ion: 1s? (b) When iron is added to copper (II) sulfate solution, the iron displaces the copper ions from solution. However, when copper is added to iron (II) sulfate solution, the iron ions are not displaced and they remain in solution. (i) Write the half equation for the reduction of copper (II) ions to form copper. (ii) Explain why the reaction takes place only if iron is added to copper (II) sulfate solution.
(a) Describe the trends of atomic size and ionization energy, respectively, in the Periodic Table: (1) from left to right across a period, and (ii) from top to bottom down a group. (b) Rank the following elements: Na, Mg, Al, and K, in increasing order of: (i) atomic size; (ii) ionization energy, and (iii) reactivity. (c) Rank the following elements: F, CI, Br and I, in increasing order of: (i) atomic size; (ii) electron affinity, (iii) electronegativity, and (iv) reactivity.
From the following list, choose the set of elements that shows the correct order of increasing first ionization energy (IE1). (A) Na < Mg < Al < Si; (B) Li < Na < K < Rb; (C) C < B < Be < Li. (D) I < Br < Cl < F;
Each electron in an atom may be characterized by a set of four quantum numbers. For each of the following parts, tell how many different sets of quantum numbers are possible, such that each set contains all the values listed: (a) n=4; (b) n=2, l=2; (c) n=2, l=0; (d) n=4, l=2, ml=+3; (e) n=4, l=3, ml=-2; (f) n=3, l=1, ml=0; (g) n=2, l=1
Calculate the energy changes when the electron transitions from the n=1 to the n=4 state for the following ions Part (a) Singly ionized helium, He+. Part (b) Doubly ionized lithium, Li++. Part (c) Triply ionized beryllium, Be+++.
18. Nitrogen has a greater first ionization energy than phosphorus. What is the best evidence to support this observation? (A) Nitrogen has a greater effective nuclear charge. (B) A nitrogen atom is larger than a phosphorus atom. (C) The electron ionized from nitrogen is in a lower energy level closer to the nucleus. (D) The electron ionized from nitrogen is not from a valence energy level. 19. Caustic soda is 20 M NaOH and is diluted for household use. What is the household concentration if 10 mL of the concentrated solution is diluted to 500 mL? (A) 0.4 M NaOH (B) 400 M NaOH (C) 4 M NaOH (D) 20 M NaOH 20. A sample of 0.0255 mol potassium hydroxide (KOH) was dissolved in water to prepare 10.0 ml of solution. What is the molarity of the solution? (A) 0.4 M (B) 2.55 M (C) 0.25 M (D) 4 M
As examples, (1) write the electronic configurations for Lithium, Neon and Silicon. (2) Indicate which subshells hold the valence electrons for each of these threeelements. (3) Contrast these three elements based on their valence electrons.
4. Chemists can identify the composition of some unknown salts by conducting a flame test. When potassium salts are heated in a flame, a purple color is observed. This is due to the movement of electrons between energy levels. What is the electron configuration of a potassium atom at ground state? (A) 1s²2s²2p63s²3p°4d! (B) 1s²2s²2p°3s?3p°3d1 (C) 1s²2s²2d®3s²3d$4s! (D) 1s²2s²2p®3s?3p°4s' atoms of gold (Au). In a 3.7-gram sample, there are (A) 1.1 x 1022 atoms of gold (B) 3.2 x 1025 atoms of gold (C) 4.4 x 1026 atoms of gold (D) 3.1 x 10-26 atoms of gold 5. 6. Which total mass is the largest? (A) The mass of 2 electrons (B) The mass of 2 neutrons (C) The mass of 1 electron plus the mass of 1 proton (D) The mass of 1 neutron plus the mass of 1 electron
34. Between 1999 and 2007 the Far Ultraviolet Spectroscopic Explorer satellite analyzed the spectra of emission sources within the Milky Way. Among the satellite's findings were interplanetary clouds containing oxygen atoms that have lost five electrons. (a) Write an electron configuration for these highly ionized oxygen atoms. (b) Which electrons have been removed from the neutral atoms? (c) The ionization energies corresponding to removal of the third, fourth, and fifth electrons are 4581 kJ/mol, 7465 kJ/mol, and 9391 kJ/mol, respectively. Explain why removal of each additional electron requires more energy than removal of the previous one. <∞0\! 8 12
7.125. How do ionization energies change with increasing atomic number (a) down a group of elements in the periodic table and (b) from left to right across a period of elements?
C. Shown below are portions of orbital of diagrams representing the ground-state electron configurations of certain elements. 1. Which of them violate(s) the Pauli Exclusion Principle? Hund's rule? Justify your answers. (a) (b) (c) 回个们们还个们们以的个 (d) (e) (f) 2. Identify the element with the electron configuration: 1s? 2s? 2pº. 3. List the values of n, I, and m, for the orbital in the 4d subshell.
(a) Write out the ground-state electron configuration (1s2, 2s2, ......) for the beryllium atom. (b) What element of next-larger Z has chemical properties similar to those of beryllium? Give the groundstate electron configuration of this element. (c) Use the procedure of part (b) to predict what element of next-larger Z than in (b) will have chemical properties similar to those of the element you found in part (b), and give its ground-state electron configuration.