For each of the following ground-state ions, predict the type of orbital \((1 \mathrm{~s}, 2 \mathrm{p}, 3 \mathrm{~d}, 4 \mathrm{f}\), etc.) from which an electron will need to be removed to form the ions of one greater positive charge: (a) \(\mathrm{Ti}^{3+} ;\) (b) \(\mathrm{In}^{+}\); (c) \(\mathrm{Te}^{2-}\); (d) \(\mathrm{Ag}^{+}\).

Understanding an atom's electronic configuration is integral to grasping atomic and chemical behaviors. With electron configuration, we map out the positions of electrons in an atom's electron shells and subshells according to their energy levels. The electrons are distributed across various orbitals such as s, p, d, and f, with each able to hold a specific number of electrons: s can hold 2, p can hold 6, d can hold 10, and f can hold 14.

When we talk about the electronic configuration of ions, it involves adding or subtracting electrons from the neutral atom's electronic configuration depending on whether the ion is positively or negatively charged. Removing electrons to form a more positively charged ion typically involves taking them from the outermost, highest energy level orbital, which reflects the order in which they were added.

The Aufbau Principle is a fundamental concept in chemistry that guides the filling of electrons into an atom's orbitals. The word 'Aufbau' is German for 'building up', and this principle states that electron orbitals are filled with electrons from the lowest energy level to the highest. It helps us predict the electronic configuration of an atom by following a specific sequence. Electrons are first placed in the lowest energy orbital available, which is typically the 1s orbital, before moving on to higher energy levels like 2s, 2p, 3s, and so on.

The removal of an electron to form a higher-charged ion will usually come from the highest energy orbital that contains electrons, effectively reversing the Aufbau process. This is because these electrons are further from the nucleus, experience less electrostatic attraction, and require less energy to remove.

Ground-state ions are ions in their lowest energy state, and they have a configuration that reflects the loss or gain of electrons when compared to the neutral atom. Positive ions, or cations, are formed by the loss of one or more electrons, leading to a deficiency in the electron count. Conversely, negative ions, or anions, are formed by the addition of electrons, resulting in a surplus.

In exercises like the one described, predicting the type of orbital for electron removal to form an ion of one greater positive charge requires understanding both the electronic configuration of the starting ion and the relative energies of the occupied orbitals. The orbital from which the electron is removed corresponds to the highest occupied energy level as per the ion's ground-state configuration.

Valence electrons are the electrons located in an atom's outermost shells. They play a key role in chemical bonding and reactions, as they are the ones involved in forming bonds with other atoms. In the context of ions, valence electrons can be either lost or gained, leading to the formation of positively or negatively charged ions, respectively.

For instance, to predict the removal of an electron for Titanium (Ti) to form a Ti^(4+) ion, we start by considering Ti^(3+) ion's valence electrons. Since Ti^(3+) would have lost electrons from its valence shell, the remaining electron in the 3d subshell is the valence electron, and hence its removal would result in Ti^(4+). Understanding the concept of valence electrons is crucial for predicting the formation and reactivity of ions.