Chapter 3

What is the energy (in kJmol \(^{-1}\) ) of X-ray photons with a wavelength of \(100 \mathrm{pm} ?\) (Section 3.2 ).

The Cl-Cl bond in \(\mathrm{Cl}_{2}\) has a bond energy of \(242 \mathrm{kJmol}^{-1}\) Assuming that absorption of photons of this energy will break the bond, what is the minimum frequency of electromagnetic radiation that is required? What part of the electromagnetic spectrum does this correspond to? (Section 3.2).

What is the wavelength of light for a line in the atomic spectrum of hydrogen for which \(n_{1}=2\) and \(n_{2}=4 ?\) What part of the electromagnetic spectrum does this correspond to? (Section 3.3)

What is the wavelength of a helium atom with a velocity of \(1.00 \times 10^{3} \mathrm{ms}^{-1} ?(\text { Section } 3.4)\)

Which of the following sets of quantum numbers are allowed? What atomic orbitals do the allowed combinations correspond to? (Section 3.5) (a) \(n=2,1=2, m_{1}=2\) (b) \(n=5, l=3, m_{1}=-2\) (c) \(n=3, l=-1, m_{1}=1\) (d) \(n=2, l=1, m_{i}=1\) (e) \(n=4, l=0, m_{1}=1\)

How many orbitals are possible for \(n=5 ?\) Identify the orbital types giving the number of each. (Section 3.5 )

For the following atomic orbitals, give the values of the quantum numbers \(n\) and \(L\) In each case indicate what values for \(m\), are allowed. (Section 3.5) (a) \(2 s\) (b) \(5 f\) (c) \(6 p\)

Using the Group 18 element shorthand, give the electronic configurations for the following elements or ions: (a) arsenic; (b) cobalt; (c) holmium; (d) bromide ion. How many unpaired electrons are there in each case? (Section 3.6)

For each of the following pairs of elements, which has the larger first ionization energy: (a) sodium and magnesium; (b) magnesium and aluminium; (c) magnesium and calcium? (Section 3.7)

Account for the following trends in ionization energy. (Section \(3.7)\) (a) The increase from oxygen to fluorine. (b) The decrease from nitrogen to phosphorus. (c) The decrease from phosphorus to sulfur.