Question

State the number of protons, electrons, and neutrons for \({ }_{8}^{17} \mathrm{O}^{2-} .\)

Short answer

The given ion \({ }_{8}^{17}\mathrm{O}^{2-}\) has \(8\) protons, \(9\) neutrons, and \(10\) electrons.

Step-by-step solution

Finding the Number of Protons

The atomic number (Z) represents the number of protons. For Oxygen, the atomic number is 8. So, there are \(8\) protons.

Finding the Number of Neutrons

The mass number (A) represents the sum of protons and neutrons. We have the mass number as 17 and the number of protons as 8. We can calculate the number of neutrons as follows: Number of neutrons = Mass number (A) - Number of protons (Z) = 17 - 8 = \(9\) neutrons

Finding the Number of Electrons

The ion has a charge of \(2-\), which tells us there are 2 more electrons than protons in the ion. Since there are 8 protons, there must be 10 electrons to result in a 2- charge. Number of electrons = Number of protons + 2 (since the ion has a 2- charge) = 8 + 2 = \(10\) electrons. The given ion \({ }_{8}^{17}\mathrm{O}^{2-}\) has \(8\) protons, \(9\) neutrons, and \(10\) electrons.

Key concepts

Protons

Protons are positively charged particles found within the nucleus of an atom. They play a crucial role in defining the element. For any given atom, the number of protons, symbolized as \( Z \) or atomic number, determines what element it is in the periodic table. For example, oxygen always has 8 protons, which is why it's represented with the atomic number 8.

Understanding protons is essential because they:

• Define the identity of an element.
• Contribute to the atomic mass along with neutrons.
• Influence the chemical behavior and reactivity of the element.

To distinguish isotopes of the same element, we look at atoms with the same number of protons but different numbers of neutrons.

Neutrons

Neutrons are neutral particles, meaning they carry no charge. They reside in the nucleus alongside protons. The number of neutrons in an atom can vary, creating isotopes of an element. These isotopes have different mass numbers due to differences in neutron count.

Here's why neutrons matter:

• They add mass to the atom without affecting its chemical properties.
• They help stabilize the nucleus, especially in heavier elements.
• Neutrons can influence the stability and radioactivity of an isotope.

Calculating the number of neutrons for an isotope is straightforward. Simply subtract the atomic number (protons count) from the mass number (sum of protons and neutrons). In the case of \({ }_{8}^{17}\mathrm{O}\), there are 9 neutrons (17 mass number - 8 protons).

Electrons

Electrons are negatively charged particles that orbit the nucleus of an atom. They play a fundamental role in determining an element's chemical properties and reactivity. Unlike protons and neutrons, electrons do not contribute significantly to atomic mass. However, their arrangement and interaction with other atoms define chemical bonds and reactions.

Key aspects of electrons include:

• They are equal in number to protons in a neutral atom.
• In ions, the electron count changes relative to the proton count, leading to an electrical charge.
• Electrons occupy energy levels or "shells" that dictate how atoms combine.

For the ion \({ }_{8}^{17}\mathrm{O}^{2-}\), the increase in electrons (10, in this case) compared to protons (8) reflects a 2- charge, which means there are 2 more electrons than protons, giving the atom its unique negative charge.