Question

Draw a Bohr model for an atom of sulfur (S). How many additional electrons can fit into the \(n=3\) shell?

Short answer

The Bohr model of a sulfur atom (S) consists of 16 protons in its nucleus and 16 electrons orbiting it in energy levels. The electrons are distributed as follows: \(n=1\) has 2 electrons, \(n=2\) has 8 electrons, and \(n=3\) has 6 electrons. The maximum number of electrons that can fit in the \(n=3\) shell is 18 electrons. Thus, 12 additional electrons can fit into the \(n=3\) shell.

Step-by-step solution

Know the Atomic Number of Sulfur

To draw a Bohr model for an atom of sulfur (S), we must first know the atomic number of sulfur. The atomic number of sulfur is 16, which means it has 16 protons and 16 electrons in a neutral atom.

Place the Electrons in Energy Levels

We will place the 16 electrons in energy levels following the principle of maximum electrons that can fit in an energy level which is given by the formula: \(2n^2\). 1. \(n=1\) shell => \(2(1)^2 = 2\) electrons 2. \(n=2\) shell => \(2(2)^2 = 8\) electrons 3. Remaining electrons => 16 - (2+8) = 6 electrons These 6 electrons will go into the \(n=3\) shell.

Draw the Bohr Model

To draw the Bohr model, first draw a circle to represent the nucleus and label it with the letter "S" for sulfur and the atomic number 16. Next, draw concentric circles around the nucleus to represent the energy levels (shells). Place electrons as dots or crosses in the orbits as follows: 1. Place 2 electrons in the first shell (n=1). 2. Place 8 electrons in the second shell (n=2). 3. Place the remaining 6 electrons in the third shell (n=3).

Determine Additional Electrons that can fit into the \(n=3\) shell

Now, we need to calculate how many additional electrons can fit into the \(n=3\) shell. Using the formula \(2n^2\), we find the maximum number of electrons that can fit into the \(n=3\) shell: \(2(3)^2 = 18\) electrons Since there are already 6 electrons in the \(n=3\) shell, we can find out the number of additional electrons that can fit in by subtracting the existing electrons from the maximum capacity: 18 - 6 = 12 additional electrons So, 12 additional electrons can fit into the \(n=3\) shell.

Key concepts

Atomic Number

The atomic number of an element is a fundamental characteristic that defines the identity of the element. In the case of sulfur, its atomic number is 16, which is essentially the number of protons found in the nucleus of an atom of sulfur. Because the number of protons determines the type of element, any atom with 16 protons is categorized as sulfur.

This atomic number also has implications for an atom's electron configuration. In a neutral atom, the number of electrons equals the number of protons so that the positive and negative charges balance out. Hence, sulfur has 16 electrons circling its nucleus. Understanding the atomic number is essential as it informs us not just about the quantity of protons and electrons an atom has, but also is the primary basis for arranging elements in the periodic table. It's the key starting point for drawing a Bohr model and for deciphering the electron configuration of an element.

Energy Levels in Atoms

Energy levels in atoms, often visualized as concentric circles around the nucleus in the Bohr model, are the specific regions where electrons reside. The principal quantum number, denoted by 'n', signifies each energy level, with 'n=1' being the closest to the nucleus and having the lowest energy.

As 'n' increases, the energy levels become further from the nucleus and can accommodate more electrons. The maximum number of electrons that can fit in a particular shell follows the formula: \(2n^2\). For the first energy level (n=1), up to 2 electrons can fit because \(2(1)^2 = 2\). The second level (n=2) can hold up to 8 electrons \(2(2)^2 = 8\), and similarly, the third level (n=3) can accommodate up to 18 electrons \(2(3)^2 = 18\). Remembering that electrons must populate the lowest available energy level first before moving to higher ones is important in understanding the structure and chemical properties of an atom.

Electron Configuration

Electron configuration describes the arrangement of electrons in an atom's energy levels or shells. It obeys several principles and rules, such as the Aufbau principle, stating electrons fill the lowest energy orbitals first. For sulfur, the electron configuration begins by filling the n=1 level with 2 electrons. The n=2 level, with more available space, is filled next with 8 electrons.

Afterward, the remaining electrons are placed in higher energy levels. In our example with sulfur, after filling the first two shells, we have 6 electrons left, so we begin to fill the n=3 shell. However, this shell is not completely filled as it can hold up to 18 electrons as per the aforementioned formula. This partially filled outer shell has implications for sulfur's chemical reactivity and the types of bonds it can form.

In instructional settings, understanding electron configuration helps students predict reactivity and the formation of compounds, which is vital for grasping more advanced concepts in chemistry.