Question

Identify the following elements. a. An excited state of this element has the electron configu- ration 1\(s^{2} 2 s^{2} 2 p^{5} 3 s^{1}\) b. The ground-state electron configuration is [Ne \(] 3 s^{2} 3 p^{4}\) . c. An excited state of this element has the electron configu- ration \([\mathrm{Kr}] 5 s^{2} 4 d^{6} 5 p^{2} 6 s^{1}\) d. The ground-state electron configuration contains three unpaired 6\(p\) electrons.

Short answer

The short answer based on the step-by-step solution is: a. The excited state electron configuration corresponds to Neon (Ne). b. The ground-state electron configuration belongs to Sulfur (S). c. The excited state electron configuration corresponds to Silver (Ag). d. The element with three unpaired 6\(p\) electrons in its ground state is Bismuth (Bi).

Step-by-step solution

a. Identify Element with Excited Electron Configuration 1\(s^{2} 2 s^{2} 2 p^{5} 3 s^{1}\) #

To find the element, we must first figure out the atomic number (number of protons) of the element. In an excited state, the element has one or more electrons at a higher energy level than its ground state. To determine the atomic number of this element, we must first find its ground state electron configuration. We need to move the 3\(s^1\) electron to the 2\(p\) orbital to achieve this configuration, which now becomes 1\(s^2 2s^2 2p^6\). The atomic number (Z) is the sum of the electron numbers: Z = 2+2+6 = 10. The element with an atomic number of 10 is Neon (Ne).

b. Identify Element with Ground-State Electron Configuration [Ne]\(3s^2 3p^4\) #

The given electron configuration includes the notation [Ne], which means the configuration starts with the electron configuration of Neon and then adds the given configuration. Since Neon's atomic number is 10, we can find the atomic number (Z) of this element by counting the electrons in the configuration: Z = 10 + 2 + 4 = 16. The element with an atomic number of 16 is Sulfur (S).

c. Identify Element with Excited Electron Configuration [Kr]\(5s^2 4d^6 5p^2 6s^1\) #

Like in part b, we are given an electron configuration that starts with [Kr], which stands for Krypton, with an atomic number of 36. We are also given an excited electron configuration, so first, we need to find the ground state configuration. To do this, move the 6\(s^1\) electron to the 4\(d\) orbital, making the configuration [Kr]\(5s^2 4d^7 5p^2\). Now find the atomic number (Z) by counting the electrons in this configuration: Z = 36 + 2 + 7 + 2 = 47. The element with an atomic number of 47 is Silver (Ag).

d. Identify Element with Three Unpaired 6\(p\) Electrons #

Since it is mentioned that the element has three unpaired 6\(p\) electrons in its ground state configuration, it must have a total of three electrons in the 6\(p\) orbital: 6\(p^3\). Counting the electron numbers from the start (filling lower energy levels first), we get the following electron configuration: 1\(s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^6 6s^2 4f^{14} 5d^{10} 6p^3\). The atomic number (Z) of this element can be calculated by counting all electrons: Z = 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 10 + 6 + 2 + 14 + 10 + 3 = 83. The element with an atomic number of 83 is Bismuth (Bi).

Key concepts

Atomic Number

The atomic number is an essential concept in understanding elements and their placement on the periodic table. It represents the number of protons present in the nucleus of an atom, and each element has a unique atomic number.
This is crucial as it defines the identity and chemical properties of the element. For example, neon has an atomic number of 10, meaning it has 10 protons.
This number also indicates the number of electrons in a neutral atom, which helps in determining electron configurations, both in ground and excited states.

Excited State

In an excited state, one or more electrons in an atom have absorbed energy. This energy causes an electron to occupy a higher energy level than its usual ground state.
Electrons in excited states are not stable and tend to return to their ground state, releasing energy. The electron configuration in an excited state differs from the ground state, as seen when a ground state electron configuration is given, and an electron is promoted to a higher orbital.
This promotion changes the way we determine the identity of an element, as we need to identify the ground state configuration first.

Ground State

The ground state is the most stable and lowest energy state of an atom, where electrons are in their closest, most natural energy levels.
Understanding the ground state electron configuration is fundamental to identifying elements. It involves arranging electrons in a way that each is in its lowest possible energy shell.
For example, sulfur has a ground-state electron configuration of [Ne]3s^2 3p^4, indicating all electrons are in their stable, lowest energy positions.

Periodic Table Elements

Elements in the periodic table are organized according to their atomic numbers, which align with their chemical properties.
This arrangement allows us to easily find elements and predict their behavior based on their position and valence electrons. Elements are grouped in families and periods, which share characteristics such as similar electron configurations in their respective ground states.
The periodic table also helps in identifying elements with specific electron configurations, as seen when finding elements with excited states or configurations with unpaired electrons, like Bismuth with its three unpaired 6p electrons.