Question

Apply Use electron configurations, orbital notation, and electron-dot structures to represent the formation of an ionic compound from the metal strontium and the nonmetal chlorine.

Short answer

The ionic compound between strontium (Sr) and chlorine (Cl) can be represented as: 1. Electron configurations: Sr: [Kr] 5s^2 Cl: [Ne] 3s^2 3p^5 2. Orbital notation: Sr: 5s: ↑↓ Cl: 3s: ↑↓; 3p: ↑ ↑ ↑; ↓ ↓ 3. Electron-dot structures: Sr: : Cl: : : x 4. Formation of the ionic compound SrCl2: Sr : + 2 ( : : Cl : x) → Sr^2+ [: : Cl^− : :]_2 Strontium donates two valence electrons to two chlorine atoms, forming Sr^2+ and Cl^− ions. The resulting compound is SrCl_2, depicted using electron configurations, orbital notation, and electron-dot structures.

Step-by-step solution

Electron configurations for strontium and chlorine

First, we will write the electron configurations for strontium (Sr) and chlorine (Cl). From a periodic table, strontium is a Group 2 element with an atomic number of 38, and chlorine is a Group 17 element with an atomic number of 17. Using the periodic table, their electron configurations can be obtained: Strontium: [Kr] 5s^2 Chlorine: [Ne] 3s^2 3p^5

Orbital notation for strontium and chlorine

Now, let's show the orbital notation for both elements. This can be done by drawing the appropriate orbitals and filling them with electrons (shown as half arrows) following the aufbau principle, the Pauli exclusion principle, and Hund's rule. Strontium: 5s: ↑↓ Chlorine: 3s: ↑↓ 3p: ↑ ↑ ↑ ↓ ↓

Electron-dot structures for strontium and chlorine

Next, we need to represent each element with its electron-dot structure, which represents the valence electrons as dots placed around the element symbol. For strontium, there are two valence electrons in the 5s orbital, while chlorine has 7 valence electrons (2 in 3s orbital and 5 in 3p orbital). Strontium: Sr : Chlorine: Cl : : x

Formation of the ionic compound

To form an ionic compound, strontium will donate its two valence electrons to chlorine, thereby achieving an electron configuration stable like that of a noble gas. Strontium will have a charge of +2 (Sr^2+), while chlorine will have a charge of -1 (Cl^−). Since the charges are not equal, we will need two chlorine atoms in order to have a balanced ionic compound (as 2+ and 2(-1) = 0). The resulting ionic compound is SrCl_2. We can show this transfer of electrons using the electron-dot structures: Sr : + 2 (: : Cl : x) → Sr^2+ [: : Cl^− : :]_2 The formation of the ionic compound strontium chloride (SrCl_2) is now depicted using electron configurations, orbital notation, and electron-dot structures.

Key concepts

Electron Configurations

Understanding electron configurations is crucial when forming ionic compounds. For strontium (Sr), which is in Group 2 of the periodic table, the atomic number is 38. This means strontium has 38 electrons. The electron configuration for strontium is \[\text{[Kr]}\,5s^2\]. Here, the \[\text{[Kr]}\] denotes the core electrons that strontium shares with krypton, and \({5s^2}\) represents its two valence electrons.

Chlorine (Cl), on the other hand, belongs to Group 17 with an atomic number of 17. Its configuration is \[\text{[Ne]}\,3s^2\,3p^5\]. Chlorine has seven valence electrons because of the \({3s^2}\) and \({3p^5}\) orbitals, making it one electron short of a stable configuration like that of argon.

Having these configurations, both elements tend to achieve a stable configuration through electron transfer, leading to the formation of an ionic compound.

Orbital Notation

Orbital notation graphically represents where electrons are located within an atom’s orbitals. Each orbital can hold two electrons of opposite spins, represented by arrows.

For strontium, you’ll find the notation:

• 5s: \(\uparrow\downarrow\)

This notation shows two electrons in the 5s orbital.

For chlorine:

• 3s: \(\uparrow\downarrow\)
• 3p: \(\uparrow\uparrow\uparrow\downarrow\downarrow\)

This represents two electrons in the 3s orbital and five electrons in the 3p orbital, with one unpaired electron available to bond.

Understanding orbital notation helps visualize how electrons are distributed and how they may interact to form an ionic bond.

Electron-Dot Structures

Electron-dot structures, also known as Lewis structures, depict valence electrons as dots around the element symbols. These structures are essential for visualizing bonding in ionic compounds.

For strontium, which has two valence electrons, the electron-dot structure is \(\text{Sr} :\). Strontium readily loses these two electrons.

Chlorine's structure is \(\text{Cl} : : \times\), showing seven valence electrons. It tends to gain one more electron to achieve an octet, represented by eight dots in total.

In the formation of an ionic compound, electrons transfer from metal to nonmetal. Strontium donates its two electrons to two chlorine atoms, resulting in \(\text{Sr}^{2+}\) and two \(\text{Cl}^-\) ions. This electron transfer can be shown as:

• \(\text{Sr} : + 2 (\text{: : Cl : \times}) \rightarrow \text{Sr}^{2+} [\text{: : Cl}^-\, \text{: :}]_2\)

Electron-dot structures effectively illustrate the formation of the ionic compound \(\text{SrCl}_2\).