Question

Identify the following three elements. a. The ground-state electron configuration is \([\mathrm{Kr}] 5 s^{2} 4 d^{10} 5 p^{4}\). b. The ground-state electron configuration is \([\mathrm{Ar}] 4 s^{2} 3 d^{10} 4 p^{2}\). c. An excited state of this element has the electron configuration \(1 s^{2} 2 s^{2} 2 p^{4} 3 s^{1}\).

Short answer

The elements corresponding to the given electron configurations are: a. Tellurium (Te) b. Germanium (Ge) c. Fluorine (F) in an excited state

Step-by-step solution

Identify the element in configuration a

For the electron configuration \([\mathrm{Kr}] 5s^2 4d^{10} 5p^4\), we need to find the total number of electrons. - There are 36 electrons in the \(\mathrm{Kr}\) shell - 2 electrons in the 5s orbital - 10 electrons in the 4d orbital - 4 electrons in the 5p orbital Adding these up gives a total of 52 electrons. According to the periodic table, the element with an atomic number of 52 is Tellurium (Te).

Identify the element in configuration b

For the electron configuration \([\mathrm{Ar}] 4s^2 3d^{10} 4p^2\), we need to find the total number of electrons. - There are 18 electrons in the \(\mathrm{Ar}\) shell - 2 electrons in the 4s orbital - 10 electrons in the 3d orbital - 2 electrons in the 4p orbital Adding these up gives a total of 32 electrons. According to the periodic table, the element with an atomic number of 32 is Germanium (Ge).

Identify the element in configuration c

For the electron configuration in the excited state \(1 s^{2} 2 s^{2} 2 p^{4} 3 s^{1}\), we need to find the total number of electrons. - There are 2 electrons in the 1s orbital - 2 electrons in the 2s orbital - 4 electrons in the 2p orbital - 1 electron in the 3s orbital (excited state) Adding these up gives a total of 9 electrons. According to the periodic table, the element with an atomic number of 9 is Fluorine (F). Please note that this is an excited state, not the ground state of Fluorine. So, the elements are: a. Tellurium (Te) b. Germanium (Ge) c. Fluorine (F) in an excited state

Key concepts

Periodic Table

The periodic table is a tabular arrangement of elements ordered by their atomic number, electron configurations, and recurring chemical properties. It's like a map for scientists, providing valuable information on how atoms of different elements relate to each other. Elements are listed in rows called periods and columns known as groups.

For students, understanding the periodic table can make the study of chemistry much more manageable. It allows you to predict the types of chemical reactions that an element might undergo, and it's essential when it comes to identifying elements based on their electron configurations, as demonstrated in the exercise with Tellurium (Te) and Germanium (Ge).

Atomic Number

The atomic number of an element is the number of protons found in the nucleus of an atom. This number is unique to each element and defines them. For instance, Oxygen will always have an atomic number of 8, meaning it has 8 protons.

In our exercise, the atomic numbers were crucial for identifying the elements based on their given electron configurations. Knowing the atomic number allows you not only to find the element in the periodic table but also to deduce the number of electrons in a neutrally charged atom, as seen with Fluorine, which has an atomic number of 9.

Ground-State Electron Configuration

Ground-state electron configuration refers to the most stable, lowest-energy arrangement of electrons in an atom. Electrons will occupy the closest orbitals to the nucleus first before moving to higher levels.

Let's consider the exercise where we identified the element with the ground-state electron configuration of \(\left[\mathrm{Kr}\right] 5s^2 4d^{10} 5p^4\). Using the atomic number (52 in this case), we know that Tellurium has this specific electron arrangement when it is in its most stable form, meaning when it's not excited or involved in a reaction. Students should be well-versed in utilizing electron configurations to predict element behaviors and properties.

Excited Electron Configuration

An 'excited' electron configuration describes an atom with one or more electrons occupying higher energy levels than they would in the ground state. When electrons absorb energy, they jump from lower to higher orbitals.

For example, in the exercise, Fluorine normally has the ground-state electron configuration of \(1s^2 2s^2 2p^5\), but was shown in an excited state as \(1s^2 2s^2 2p^4 3s^1\). Recognizing such changes is key in explaining the behavior of atoms under various energy influences, and illustrates the dynamic nature of electron arrangements beyond their most stable forms.