Which of the alternatives below identifies the electron configuration of the cation and anion present in the compound magnesium oxide?

\begin{align*}
\begin{array}{l}
\rule{0pt}{2.5ex} \ \rule[-1ex]{0pt}{0pt}& \\
\rule{0pt}{2.5ex}\textbf{A.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{B.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{C.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{D.}\rule[-1ex]{0pt}{0pt}\\
\end{array}
\begin{array}{|c|c|}
\hline
\rule{0pt}{2.5ex}\text{Cation}\rule[-1ex]{0pt}{0pt}& \text{Anion} \\
\hline
\rule{0pt}{2.5ex} 1s^2\,2s^2\,2p^6\,3s^1\rule[-1ex]{0pt}{0pt}& 1s^2\,2s^2\,2p^6\\
\hline
\rule{0pt}{2.5ex} 1s^2\,2s^2\,2p^6\rule[-1ex]{0pt}{0pt}& 1s^2\,2s^2\,2p^6\\
\hline
\rule{0pt}{2.5ex} 1s^2\,2s^2\,2p^6\,3s^2\rule[-1ex]{0pt}{0pt}& 1s^2\,2s^2\,2p^4 \\
\hline
\rule{0pt}{2.5ex} 1s^2\,2s^2\,2p^6\rule[-1ex]{0pt}{0pt}& 1s^2\,2s^2\,2p^6\,3s^2\,3p^6 \\
\hline
\end{array}
\end{align*}

What is the electron configuration of the element with atomic number 34?

1. \(1s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 3d^{10}\, 4p^4\)
2. \(1s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 3d^9\, 4p^5\)
3. \(1s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 3d^6\, 4p^2\)
4. \(1s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 4p^{4}\, 4d^{10}\)

A calcium ion, \(\ce{Ca^{2+}}\), has an atomic number of 20 and a mass number of 40. Which of the following statements is correct?

1. A calcium ion has 20 protons, 20 electrons and 20 neutrons
2. A calcium ion has 20 protons, 18 electrons and 20 neutrons
3. A calcium ion has 18 protons, 20 electrons and 20 neutrons
4. A calcium ion has 20 protons, 18 electrons and 18 neutrons

Which element has the following electronic configuration.

\(1s^2\) \(2s^2\) \(2p^6\) \(3s^2\) \(3p^1\)

1. Sodium
2. Magnesium
3. Aluminium
4. Silicon

Write the electronic configuration for the following substances, using spdf notation:

1. Calcium atom   (1 mark)

2. Fluoride ion   (1 mark)

Three electron configurations are presented in the table. For elemental titanium, the ground state is represented by \(\text{I}\), while \(\text{II}\) and \(\text{III}\) are both invalid ground state electron configurations.
 

Write a valid electron configuration for \(\ce{Ti^3+}\).  (2 marks)

The electron spin orbital diagram represents the \(3d\) and \(4s\) electrons for an element in the first transition series.

Identify this element and explain the arrangement of electrons in these sub-shells in terms of the Pauli exclusion principle and Hund's rule.   (3 marks)

The diagram below shows the ground state electron configuration of two complexes of cobalt in aqueous solution.
 

Identify the block in the periodic table to which cobalt belongs and write the electron configuration of cobalt metal in its ground state.  (2 marks)

Write the full electron configurations for a \(\ce{Ca}\) atom in the ground state, an excited \(\ce{Ca}\) atom and a \( \ce{Ca}^{+}\) ion.  (2 marks)

What is the maximum number of electrons that a p-orbital can hold?  (1 mark)

Explain the fact that Group I and Group II metal ions have one oxidation state while the transition metals often have multiple oxidation states.  (3 marks)

Identify ONE cation and ONE anion that can be represented by the electron configuration \( \ce{1 s^2 2 s^2 2 p^6 3 s^2 3 p^6} \).  (2 marks)

An atom has FIVE valence electrons in its \(d\) orbital. Using an orbital diagram of the valence shell of the atom, explain how Hund's rule determines the electronic configuration.   (3 marks)

Identify in which of the \( s, p, d \) or \(f \) blocks of the Periodic Table the element \(\ce{Ra}\) is found. Justify your answer.   (2 marks)