Moseley established the concept of atomic number by studying X rays emitted by the elements. The X rays emitted by some of the elements have the following wavelengths: Element Wavelength (pm) Ne 1461 Ca 335.8 Zn 143.5 Zr 78.6 Sn 49.1 (e) A particular element emits X rays with a wavelength of 98.0 pm. What element do you think it is?

Which of these spheres represents F, which represents Br, and which represents Br-?

Consider the Mg²⁺, Cl^-, K⁺, and Se^2- ions. The four spheres below represent these four ions, scaled according to ionic size. (b) In terms of size, between which of the spheres would you find the (i) Ca²⁺ and (ii) S^2- ions?

In the following reaction

which sphere represents a metal and which represents a nonmetal?

Shown below is a qualitative diagram of the atomic orbital energies for an Na atom. The number of orbitals in each subshell is not shown.

(d) A sodium vapor lamp (Figure 7.23) operates by using electricity to excite the highest-energy electron to the next highest-energy level. Light is produced when the excited electron drops back to the lower level. Which two energy levels are involved in this process for the Na atom?

The prefix eka- comes from the Sanskrit word for 'one.' Mendeleev used this prefix to indicate that the unknown element was one place away from the known element that followed the prefix. For example, eka-silicon, which we now call germanium, is one element below silicon. Mendeleev also predicted the existence of eka-manganese, which was not experimentally confirmed until 1937 because this element is radioactive and does not occur in nature. Based on the periodic table shown in Figure 7.1, what do we now call the element Mendeleev called eka-manganese?

Which of the following statements about effective nuclear charge for the outermost valence electron of an atom is incorrect? (i) The effective nuclear charge can be thought of as the true nuclear charge minus a screening constant due to the other electrons in the atom. (ii) Effective nuclear charge increases going left to right across a row of the periodic table. (iii) Valence electrons screen the nuclear charge more effectively than do core electrons. (iv) The effective nuclear charge shows a sudden decrease when we go from the end of one row to the beginning of the next row of the periodic table. (v) The change in effective nuclear charge going down a column of the periodic table is generally less than that going across a row of the periodic table

Detailed calculations show that the value of Zeff for the outermost electrons in Na and K atoms is 2.51+ and 3.49+, respectively. (e) Predict Zeff for the outermost electrons in the Rb atom based on the calculations for Na and K.

Detailed calculations show that the value of Zeff for the outermost electrons in Si and Cl atoms is 4.29+ and 6.12+, respectively. (a) What value do you estimate for Zeff experienced by the outermost electron in both Si and Cl by assuming core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant?

With the exception of helium, the noble gases condense to form solids when they are cooled sufficiently. At temperatures below 83 K, argon forms a close-packed solid whose structure is shown below. (b) Is this value larger or smaller than the bonding atomic radius estimated for argon in Figure 7.7?

With the exception of helium, the noble gases condense to form solids when they are cooled sufficiently. At temperatures below 83 K, argon forms a close-packed solid whose structure is shown below. (c) Based on this comparison would you say that the atoms are held together by chemical bonds in solid argon?

Tungsten has the highest melting point of any metal in the periodic table: 3422 °C. The distance between W atoms in tungsten metal is 274 pm. (a) What is the atomic radius of a tungsten atom in this environment? (This radius is called the metallic radius.)

Tungsten has the highest melting point of any metal in the periodic table: 3422 °C. The distance between W atoms in tungsten metal is 274 pm. (b) If you put tungsten metal under high pressure, predict what would happen to the distance between W atoms.

Which of the following statements about the bonding atomic radii in Figure 7.7 is incorrect? (i) For a given period, the radii of the representative elements generally decrease from left to right across a period. (ii) The radii of the representative elements for the n = 3 period are all larger than those of the corresponding elements in the n = 2 period. (iii) For most of the representative elements, the change in radius from the n = 2 to the n = 3 period is greater than the change in radius from n = 3 to n = 4. (iv) The radii of the transition elements generally increase moving from left to right within a period. (v) The large radii of the Group 1 elements are due to their relatively small effective nuclear charges.

Estimate the As¬I bond length from the data in Figure 7.7 and compare your value to the experimental As ¬I bond length in arsenic triiodide, AsI₃, 2.55 Å.

Using only the periodic table, arrange each set of atoms in order from largest to smallest: (c) F, O, N.

Using only the periodic table, arrange each set of atoms in order of increasing radius: (b) S, Si, Sr

Identify each statement as true or false: (a) Cations are larger than their corresponding neutral atoms.

Identify each statement as true or false: (b) Li⁺ is smaller than Li.

Use data from Appendix C, Figure 7.10, and Figure 7.12 to calculate the lattice energy of RbCl.

Which neutral atom is isoelectronic with each of the following ions? Ga³⁺, Zr⁴⁺, Mn⁷⁺, I⁻, Pb²⁺.

Some ions do not have a corresponding neutral atom that has the same electron configuration. For each of the following ions, identify the neutral atom that has the same number of electrons and determine if this atom has the same electron configuration. (a) CI⁻, (b) Sc³⁺, (c) Fe²⁺, (d) Zn²⁺, (e) Sn⁴⁺.

Consider the isoelectronic ions F- and Na+. (b) Using Equation 7.1 and assuming that core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant, S, calculate Zeff for the 2p electrons in both ions.

Consider the isoelectronic ions F- and Na+. (d) For isoelectronic ions, how are effective nuclear charge and ionic radius related?

Consider S, Cl, and K and their most common ions. (a) List the atoms in order of increasing size.