Write the ground-state electron configurations of the following transition metal ions: (a) $\mathrm{Sc}^{3+}$, (b) $\mathrm{Ti}^{4+}$, (c) $\mathrm{V}^{5+}$, (d) $\mathrm{Cr}^{3+}$, (e) $\mathrm{Mn}^{2+}$, (f) $\mathrm{Fe}^{2+}$, (g) $\mathrm{Fe}^{3+}$, (h) $\mathrm{Co}^{2+}$, (i) $\mathrm{Ni}^{2+}$, (j) $\mathrm{Cu}^{+}$, (k) $\mathrm{Cu}^{2+}$, (l) $\mathrm{Ag}^{+}$, (m) $\mathrm{Au}^{+}$, (n) $\mathrm{Au}^{3+}$, (o) $\mathrm{Pt}^{2+}$.

Write the ground-state electron configurations for the following transition metal ions: $\mathrm{Sc}^{3+}, \mathrm{Ti}^{4+}, \mathrm{V}^{5+}$, $\mathrm{Cr}^{3+}, \mathrm{Mn}^{2+}, \mathrm{Cu}^{+}, \mathrm{Ag}^{+}, \mathrm{Au}^{+}, \mathrm{Au}^{3+}$, and $\mathrm{Pt}^{2+}$.

What is the smallest atom in periodic table?

The electron configurations described in this chapter all refer to gaseous atoms in their ground states. An atom may absorb a quantum of energy and promote one of its electrons to a higher-energy orbital. When this happens, we say that the atom is in an excited state. The electron configurations of some excited atoms are given. Identify these atoms and write their ground-state configurations: (a) $1s^12s^1$
(b) $1s^22s^22p^23d^1$ (c) $1s^22s^22p^64s^1$ (d) $[\mathrm{Ar}]4s^13d^{10}4p^4$ (e) $[\mathrm{Ne}]3s^23p^43d^1$

The electron configurations described in Chapter 2 all refer to gaseous atoms in their ground states. An atom may absorb a quantum of energy and promote one of its electrons to a higher-energy orbital. When this happens, we say that the atom is in an excited state. The electron configurations of some excited atoms are given. Identify these atoms and write their ground-state configurations:
$1 s^2 2 s^2 2 p^2 3 d^1$.

When a certain paramagnetic material is placed in an external magnetic field of $1.5000 \mathrm{~T}$, the field inside the material is measured to be $1.5023 \mathrm{~T}$. Find $(a)$ the relative permeability and $(b)$ the magnetic permeability of this material.

When a magnet is thrust into a coil as in given figure, what is the direction of the force exerted by the coil on the magnet? Draw a diagram showing the direction of the current induced in the coil and the magnetic field it produces, to justify your response. How does the magnitude of the force depend on the resistance of the galvanometer?

Write the ground-state electron configurations of the following ions, which play important roles in biochemical processes in our bodies: (a) $\mathrm{Na}^{+}$, (b) $\mathrm{Mg}^{2+}$, (c) $\mathrm{Cl}^{-}$, (d) $\mathrm{K}^{+}$, (e) $\mathrm{Ca}^{2+}$, (f) $\mathrm{Fe}^{2+}$, (g) $\mathrm{Cu}^{2+}$, (h) $\mathrm{Zn}^{2+}$.

Write the ground-state electron configurations of the following ions: (a) $\mathrm{Li}^{+}$, (b) $\mathrm{H}^{-}$, (c) $\mathrm{N}^{3-}$, (d) $\mathrm{F}^{-}$, (e) $\mathrm{S}^{2-}$, (f) $\mathrm{Al}^{3+}$, (g) $\mathrm{Se}^{2-}$, (h) $\mathrm{Br}^{-}$, (i) $\mathrm{Rb}^{+}$, (j) $\mathrm{Sr}^{2+}$, (k) $\mathrm{Sn}^{2+}$, (l) $\mathrm{Te}^{2-}$, (m) $\mathrm{Ba}^{2+}$, (n) $\mathrm{Pb}^{2+}$, (o) $\mathrm{In}^{3+}$, (p) $\mathrm{Tl}^{+}$, (q) $\mathrm{Tl}^{3+}$.

A metal ion with a net +3 charge has five electrons in the 3d sub-shell. Identify the metal.

A $\mathrm{M}^{2+}$ ion derived from a metal in the first transition metal series has four electrons in the 3d subshell. What element might M be?

Explain why the ground-state electron configurations of Cr and Cu are different from what we might expect.

Explain why the ground state electron configurations of Cr and Cu are different from what we might expect.

In the periodic table the element hydrogen is sometimes grouped with the alkali metals and sometimes with the halogens. Explain why hydrogen can resemble the Group 1A and the Group 7A elements.