Problem 178 - Introductory Chemistry Atoms First

Question

What is the total number of \(p\) -subshell electrons for each of the following atoms: \(\mathrm{P}, \mathrm{Mg}\), Se, \(\mathrm{Zn} ?\)

Step-by-Step Solution

Answer

Phosphorus (P) has 9 p-subshell electrons, Magnesium (Mg) has 6 p-subshell electrons, Selenium (Se) has 16 p-subshell electrons, and Zinc (Zn) has 12 p-subshell electrons.

Step 1: Find the atomic numbers of the given elements

First, we need to determine the atomic numbers (number of protons) of the given elements. This information can be found on the periodic table. For Phosphorus (P), the atomic number is 15. For Magnesium (Mg), the atomic number is 12. For Selenium (Se), the atomic number is 34. For Zinc (Zn), the atomic number is 30.

Step 2: Determine the electron configurations

Now that we have the atomic numbers of the given elements, we can determine their electron configurations. - P: (Atomic number = 15) => 1s^2 2s^2 2p^6 3s^2 3p^3 - Mg: (Atomic number = 12) => 1s^2 2s^2 2p^6 3s^2 - Se: (Atomic number = 34) => 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^4 - Zn: (Atomic number = 30) => 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10

Step 3: Count the number of p-subshell electrons

Now, we can count the number of p-subshell electrons by looking for p-orbitals in the electron configurations we've found in Step 2. - P: has a 2p^6 and 3p^3 => 6 (from 2p) + 3 (from 3p) = 9 p-subshell electrons - Mg: has a 2p^6 => 6 p-subshell electrons - Se: has a 2p^6, 3p^6, and 4p^4 => 6 (from 2p) + 6 (from 3p) + 4 (from 4p) = 16 p-subshell electrons - Zn: has a 2p^6 and 3p^6 => 6 (from 2p) + 6 (from 3p) = 12 p-subshell electrons

Step 4: Present the final results

Now that we have the total number of p-subshell electrons for each given element, we can present our final results. - Phosphorus (P) has 9 p-subshell electrons - Magnesium (Mg) has 6 p-subshell electrons - Selenium (Se) has 16 p-subshell electrons - Zinc (Zn) has 12 p-subshell electrons

Key Concepts

Periodic Table

The Periodic Table is a vital tool in chemistry that organizes all known elements. Each element is placed in order of increasing atomic number, which correlates to the number of protons in an atom's nucleus. By consulting the Periodic Table, you can learn not only about the atomic number but also the electronic structure and properties of elements.

Here are some useful points about the Periodic Table:

• Elements are arranged in rows called periods and columns known as groups.
• The position of an element on the table reveals if it is a metal, non-metal, or metalloid.
• Information on element symbols, atomic numbers, and atomic weights is readily available.

In exercises involving electron configurations, like calculating p-subshell electrons, the Periodic Table helps to first find atomic numbers, which then inform the electron configuration.

p-subshell

Electron configurations denote the distribution of electrons among the atom's orbitals. A p-subshell refers specifically to a group of orbitals within an electron shell that can hold up to six electrons.

This is crucial in exercises assessing the total number of p-subshell electrons for elements:

• Elements like Phosphorus (P) and Selenium (Se) show these subshells filled to different extents.
• The electrons fill the 2p, 3p, etc., orbitals in keeping with their overall electron configuration.
• Knowledge of electron configuration helps discern how electrons meet other elements to form bonds.

The ability to read and understand electron configurations, specifically how many electrons populate each subshell, enhances one's understanding of chemical properties and reactivity.

Atomic Number

The Atomic Number is one of the most fundamental concepts in chemistry. It represents the number of protons in the nucleus of an atom and serves as a unique identifier for each element. For example, Phosphorus has an atomic number of 15, indicating it has 15 protons.

Understanding atomic numbers is key for several reasons:

• It determines the element's position on the Periodic Table.
• It indicates the number of electrons in a neutral atom, affecting its electron configuration.
• In calculating p-subshell electrons, starting with the atomic number allows accurate determination of the electron configuration and distribution in the atom's outer shells.

The atomic number ultimately guides the behavior of atoms during chemical reactions, making it a central concept for solving many chemistry problems.