Question

Write the complete orbital diagram for each of the following elements, using boxes to represent orbitals and arrows to represent electrons. a. aluminum, \(Z=13\) b. phosphorus, \(Z=15\) c. bromine, \(Z=35\) d. argon, \(Z=18\)

Short answer

a. Aluminum: 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑ b. Phosphorus: 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑ ↑ ↑ c. Bromine: 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑↓ ↑↓ ↑↓ 4s → ↑↓ 3d → ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4p → ↑↓ ↑↓ ↑↑ d. Argon: 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑↓ ↑↓ ↑↓

Step-by-step solution

Electron configuration

Determine the electron configuration for aluminum, which has an atomic number of 13, representing 13 electrons in its neutral state. The electron configuration is written as: 1s²2s²2p⁶3s²3p¹

Draw the orbital diagram

Now, let's draw the orbital diagram for aluminum. Use boxes to represent orbitals and arrows (up or down) to represent electrons. 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑ b. Phosphorus, \(Z=15\)

Electron configuration

Determine the electron configuration for phosphorus, which has an atomic number of 15, representing 15 electrons in its neutral state. The electron configuration is written as: 1s²2s²2p⁶3s²3p³

Draw the orbital diagram

Now, let's draw the orbital diagram for phosphorus. Use boxes to represent orbitals and arrows (up or down) to represent electrons. 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑ ↑ ↑ c. Bromine, \(Z=35\)

Electron configuration

Determine the electron configuration for bromine, which has an atomic number of 35, representing 35 electrons in its neutral state. The electron configuration is written as: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵

Draw the orbital diagram

Now, let's draw the orbital diagram for bromine. Use boxes to represent orbitals and arrows (up or down) to represent electrons. 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑↓ ↑↓ ↑↓ 4s → ↑↓ 3d → ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4p → ↑↓ ↑↓ ↑↑ d. Argon, \(Z=18\)

Electron configuration

Determine the electron configuration for argon, which has an atomic number of 18, representing 18 electrons in its neutral state. The electron configuration is written as: 1s²2s²2p⁶3s²3p⁶

Draw the orbital diagram

Now, let's draw the orbital diagram for argon. Use boxes to represent orbitals and arrows (up or down) to represent electrons. 1s → ↑↓ 2s → ↑↓ 2p → ↑↓ ↑↓ ↑↓ 3s → ↑↓ 3p → ↑↓ ↑↓ ↑↓

Key concepts

Electron Configuration

Electron configuration is a way to describe the distribution of electrons in an atom. This is crucial for understanding the chemical properties and behaviors of different elements. Electrons are arranged in different energy levels or shells around the nucleus, and these shells are further divided into subshells, such as s, p, d, and f. Each of these subshells can hold a specific number of electrons (for instance, s holds 2, p holds 6).

• The configuration starts from 1s, then 2s, 2p, followed by 3s, and so on, filling in sequence based on increasing energy levels.
• Understanding electron configuration helps in predicting how an atom might interact chemically with other atoms.

In the exercise, the electron configuration for elements like aluminum, phosphorus, bromine, and argon was identified. For aluminum, with 13 electrons, it is 1s²2s²2p⁶3s²3p¹. This tells us that the first and second energy levels are full while the third one is only partially filled.

Atomic Number

The atomic number, denoted as \(Z\), is a fundamental property of an element. It represents the number of protons in the nucleus of an atom. In a neutral atom, this is also equal to the number of electrons.

• The atomic number is unique to each element, defining its identity.
• For example, aluminum has an atomic number of 13, meaning it has 13 protons and, usually in a neutral state, 13 electrons.

When you know the atomic number, you can easily determine the element's position on the periodic table, its chemical behavior, and its electron configuration.

Neutral State

An atom is in a neutral state when it has an equal number of protons and electrons. In this state, the positive charges of the protons balance out the negative charges of the electrons, resulting in a net charge of zero.

• This neutral state is natural for most atoms unless they gain or lose electrons during chemical reactions forming ions.
• For example, the elements in the exercise -- aluminum with 13, phosphorus with 15, bromine with 35, and argon with 18 electrons each -- are in their neutral state, fully mirroring their atomic numbers.

Being in a neutral state affects how the electron configuration and orbital diagrams are depicted as they accurately represent the true electron count for each atom.

Electron Configuration Notation

Electron configuration notation is a shorthand statement that describes an element’s electron arrangement. It uses numbers and letters to indicate the energy levels and subshells occupied by electrons.

• For example, 1s²2s² indicates two electrons in the first energy level's s subshell and another two in the second energy level's s subshell.
• It helps chemists quickly convey the arrangement of electrons without showing the detailed orbital diagram.

In the step-by-step solutions, configurations like 1s²2s²2p⁶3s²3p¹ used for aluminum illuminate how electrons fill orbitals from lower to higher energies, complying with the Aufbau principle. Such notations provide a foundational understanding of how atoms bond and react.