Question

For the following processes that show the formation of ions, fill in the number of electrons that must be lost or gained to complete the process. a. $\mathrm{Co}\to {\mathrm{Co}}^{2+}+$ _________$-e$ b. $N+$__________ ${\mathrm{e}}^{-}\to {\mathrm{N}}^{3-}$ c. $\mathrm{Sn}\to {\mathrm{Sn}}^{2+}+$________$e^{-}$. d. $\mathrm{sn}\to {\mathrm{sn}}^{4+}+$_________$e^{-}$. e. $Rb\to R{b}^{+}+$_______$e^{-}$. e. $Rb\to R{b}^{+}+$________$e^{-}$. f. $S+$ __________ ${\mathrm{e}}^{-}\to {\mathrm{S}}^{2-}$

Short answer

a. $2$ b. $3$ c. $2$ d. $4$ e. $1$ f. $2$

Step-by-step solution

Identify the group number of the element in the periodic table

For each element given (Co, N, Sn, Rb, and S), identify the group number in the periodic table. The group number tells us the number of valence electrons the neutral atom has.

Determine the final number of valence electrons after ion formation

Since we are given the charge of the ion after the process, we can determine how many valence electrons the ion has. For example, if an ion has a charge of +2, it has lost two electrons; if an ion has a charge of -2, it has gained two electrons. Add or subtract the charge from the number of valence electrons.

Calculate the number of electrons gained or lost

Finally, subtract the number of valence electrons in the ion from the number of valence electrons in the neutral atom. This will give us the number of electrons gained or lost. Now, let's proceed to solve the problems: a. Co → Co²⁺ + _______-e Group number: 9 (Co has 9 valence electrons) Final valence electrons: 9 - 2 = 7 Electrons gained or lost: 9 - 7 = 2 electrons lost, so the answer is 2. b. N + _______ e⁻ → N³⁻ Group number: 5 (N has 5 valence electrons) Final valence electrons: 5 + 3 = 8 Electrons gained or lost: 8 - 5 = 3 electrons gained, so the answer is 3. c. Sn → Sn²⁺ + _______e⁻ Group number: 14 (Sn has 4 valence electrons) Final valence electrons: 4 - 2 = 2 Electrons gained or lost: 4 - 2 = 2 electrons lost, so the answer is 2. d. Sn → Sn⁴⁺ + _______e⁻ Group number: 14 (Sn has 4 valence electrons) Final valence electrons: 4 - 4 = 0 Electrons gained or lost: 4 - 0 = 4 electrons lost, so the answer is 4. e. Rb → Rb⁺ + _______e⁻ Group number: 1 (Rb has 1 valence electron) Final valence electrons: 1 - 1 = 0 Electrons gained or lost: 1 - 0 = 1 electron lost, so the answer is 1. f. S + _______e⁻ → S²⁻ Group number: 16 (S has 6 valence electrons) Final valence electrons: 6 + 2 = 8 Electrons gained or lost: 8 - 6 = 2 electrons gained, so the answer is 2.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and play a critical role in chemical bonding. These electrons are involved in forming bonds, as they can be gained, lost, or shared during chemical reactions. The number of valence electrons determines an element's chemical properties and how it interacts with other elements.

• The group number in the periodic table indicates the number of valence electrons for the main-group elements. For example, elements in Group 1 have 1 valence electron, while those in Group 17 have 7 valence electrons.
• In the case of transition metals, the situation is a bit more complex, as these elements have valence electrons that reside in both the outermost and inner shells.

Understanding the concept of valence electrons is essential because it helps predict how an element will react during the ion formation process.

Electron Gain or Loss

Ion formation involves the gain or loss of electrons, transforming an atom into an ion. This process occurs to reach a stable electronic configuration, usually resembling the nearest noble gas.

• Atoms lose electrons to form positively charged ions called cations. For instance, lithium ( ext{Li}) loses one electron to form ext{Li}^+.
• Atoms gain electrons to form negatively charged ions called anions. For example, oxygen ( ext{O}) gains two electrons to form ext{O}^{2-}.

The decision for an atom to lose or gain electrons depends on its position in the periodic table and its desire to achieve an octet configuration. This is when an atom has 8 valence electrons, providing high stability.

Periodic Table

The periodic table is an organized chart of elements that provides a wealth of information about every element, including their atomic number, chemical properties, and electronic configuration.

• Each element's position in the periodic table gives insight into the number of valence electrons, which is crucial for understanding chemical reactivity and ion formation.
• The elements are arranged in order of increasing atomic number, and elements in the same column (group) typically have similar chemical and physical properties.

Understanding the layout and information provided by the periodic table is fundamental in predicting how elements will react and form ions.

Electrons

Electrons are subatomic particles with a negative charge that orbit the nucleus of an atom. They play a decisive role in chemical bonding and reactions.

• In neutral atoms, the number of electrons equals the number of protons, giving the atom no net electrical charge.
• Electrons move in orbitals around the nucleus, and their arrangement in these orbitals determines how atoms interact and bond with each other.
• When atoms lose or gain electrons, they become ions with either a positive or negative charge. The charge results from the imbalance between the number of protons and electrons.

By moving to achieve a stable electron arrangement, electrons influence the chemical properties and behaviors of elements and compounds.