Problem 85 - General Chemistry: Principles and Modern Applications

Question

What is the expected ground-state electron configuration for each of the following elements? (a) mercury; (b) calcium; (c) polonium; (d) tin; (e) tantalum; (f) iodine.

Step-by-Step Solution

Answer

The electron configurations are: Mercury: \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6 6s^2 4f^{14} 5d^{10}\], Calcium: \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2\], Polonium: \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^6 4f^{14} 5d^{10} 6s^2 6p^4\], Tin: \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^2\], Tantalum: \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 4f^{14} 5s^2 5p^6 5d^{3} 6s^2\], Iodine: \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^{5}\]

Step 1: Mercury Electron Configuration

Mercury is element number 80 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6 6s^2 4f^{14} 5d^{10}\]

Step 2: Calcium Electron Configuration

Calcium is element number 20 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2\]

Step 3: Polonium Electron Configuration

Polonium is element number 84 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^6 4f^{14} 5d^{10} 6s^2 6p^4\]

Step 4: Tin Electron Configuration

Tin is element number 50 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^2\]

Step 5: Tantalum Electron Configuration

Tantalum is element number 73 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 4f^{14} 5s^2 5p^6 5d^{3} 6s^2\]

Step 6: Iodine Electron Configuration

Iodine is element number 53 on the Periodic Table. Its electron configuration is \[1s^2 2s^2 2p^6 3s^2 3p^6 3d^{10} 4s^2 4p^6 4d^{10} 5s^2 5p^{5}\]

Key Concepts

Periodic Table

The periodic table is a systematic arrangement of elements in order of increasing atomic number. The elements are placed in rows, known as periods, and columns, referred to as groups. Understanding the periodic table is crucial for determining an element's electron configuration. Why? Because the table's layout reflects the sequential filling of electron orbitals.

It's not just about remembering placements. Each element's position tells us about its atomic structure and chemical properties.

• **Periods:** These are horizontal rows that signify the number of electron shells. For instance, calcium (Ca) is in period 4, indicating it has four electron shells.
• **Groups:** These vertical columns reflect elements with similar chemical behaviors, partly due to having the same number of valence electrons.

The blocks of the table—s, p, d, and f—help us track the filling order of electron orbitals. When moving right across a period, electrons fill these sub-levels in this order, inherited in the same block sequence.
Understanding this predictive layout aids chemists and students in studying elements' behaviors and their interactions.

Ground-State Electrons

Ground-state electrons are those in the lowest energy configuration possible. This principle is essential in chemistry, as it predicts how atoms behave in their most stable form. When determining electron configurations, we're identifying the precise distribution of electrons in atom's orbitals.

Here’s how it works:- **Aufbau Principle:** Helps predict the order of electron filling. Starting from the lowest energy levels and moving to higher ones, that's the approach for filling electron orbitals.- **Pauli Exclusion Principle:** States that each orbital can hold a maximum of two electrons with opposite spins.- **Hund's Rule:** When electrons occupy orbitals of equal energy, one electron enters each orbital until all are half-filled before pairing up.

By using these principles, chemists can determine the electron configuration of an atom in its ground state, like mercury (Hg): **Configuration:** \[1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6 6s^2 4f^{14} 5d^{10}\]This allows us to predict how atoms will engage in chemical bonds and reactions.

Element Properties

Element properties are various characteristics that define an element, including its physical state, reactivity, and behavior in chemical reactions. These properties are often categorized by trends that are observable across the periodic table.

For example, the electron configuration of an element can reveal much about its properties:

• **Valency:** Determines how an element interacts, or combines, with others. Elements with similar valencies fall into the same group on the periodic table.
• **Electronegativity and Ionization Energy:** These properties tend to increase across a period and decrease down a group.
• **Atomic Radius:** Typically decreases across a period but increases down a group, due to the addition of electron shells.

The properties that each element possesses are a direct result of its electron configuration and its position on the periodic table. This is why elements like tin (Sn) in pure form are widely used for coating other metals to prevent corrosion, due to its stable electron configuration and chemical stability. Such properties are invaluable when seeking materials for specific functions in industries or chemical experiments.