Question

State the predicted ionic charge of nonmetal ions in each of the following groups of elements: (a) Group IVA/14 (b) Group \(\mathrm{VA} / 15\) (c) Group VIA/16 (d) Group VIIA/17

Short answer

Group IVA/14 nonmetals generally do not form ions, Group VA/15 ions are \(-3\), Group VIA/16 ions are \(-2\), and Group VIIA/17 ions are \(-1\).

Step-by-step solution

Understanding Group IVA/14

Elements in Group IVA/14 have four valence electrons. When they form ions, they can either gain or lose electrons. However, for nonmetals in this group, like carbon and silicon, they are more likely to form covalent bonds rather than ionic. Thus, nonmetals in Group IVA/14 do not have a typical ionic charge.

Analyzing Group VA/15

Group VA/15 elements have five valence electrons. Nonmetals in this group, particularly nitrogen and phosphorus, typically gain three electrons to achieve a stable octet. Thus, the resulting ionic charge for these nonmetal ions is \(-3\).

Reviewing Group VIA/16

Group VIA/16 elements possess six valence electrons. Nonmetals such as oxygen and sulfur are likely to gain two electrons to fill their valence shell, achieving the stable octet configuration. Consequently, their typical ionic charge is \(-2\).

Evaluating Group VIIA/17

Nonmetals in Group VIIA/17, like fluorine and chlorine, have seven valence electrons. They typically gain one electron to complete their octet. Therefore, these elements form ions with a \(-1\) charge.

Key concepts

Nonmetal Ions

Nonmetal ions are atoms of nonmetals that have gained electrons to become negatively charged. These ions form when nonmetals swap valence electrons, which are the outermost electrons of an atom, to reach a stable state. In general, nonmetals prefer to gain electrons rather than lose them. This is because gaining electrons helps them achieve a more stable electron arrangement.
When nonmetals form ions, they always carry a negative charge. The number of electrons gained will determine the magnitude of this negative charge. Nonmetals in different groups have different tendencies to gain a specific number of electrons to reach their stable state.

Valence Electrons

Valence electrons play a key role in the chemical behavior of an atom. They are the electrons located in the outermost shell and are involved in forming bonds with other atoms. The number of valence electrons determines how an element interacts with others.
For nonmetals, the goal is to fill their outermost shell with electrons to become more stable. As you move from left to right in the periodic table, the number of valence electrons in nonmetals increases:

• Group IVA/14 elements like carbon have four valence electrons.
• Group VA/15 elements like nitrogen have five valence electrons.
• Group VIA/16 elements like oxygen have six valence electrons.
• Group VIIA/17 elements like fluorine have seven valence electrons.

Understanding valence electrons helps us predict how elements will form ions and the type of bonds they will create.

Stable Octet

The concept of a stable octet is crucial in understanding why atoms form ions. A stable octet means having eight electrons in an atom's outermost shell, which provides stability. This is based on the electron configuration of noble gases, which are naturally stable due to having complete valence shells.
Nonmetals aim to achieve this stable octet configuration when forming ions. For example, nitrogen in Group VA/15 has five valence electrons and needs three more to complete its octet. This results in the nitrogen ion having a charge of (-3). The number of electrons needed to reach a stable octet often guides how nonmetals find partners to bond with, thereby determining the ionic charges they form.

Periodic Table Groups

The periodic table groups are vertical columns that classify elements based on similar properties and the number of valence electrons. Each group provides critical insights into the chemical behavior of its elements, especially nonmetals.
In nonmetals, this classification helps predict ionic charges by pointing out how many electrons an element needs to gain to achieve a stable octet:

• Group IVA/14 normally does not form strong ionic charges.
• Group VA/15 gains three electrons with an ionic charge of (-3).
• Group VIA/16 gains two electrons with an ionic charge of (-2).
• Group VIIA/17 gains one electron with an ionic charge of (-1).

The periodic table groups are a helpful tool for understanding and predicting the behavior of elements.