Chapter 2: Problem 91
One isotope of a nonmetallic element has mass number 31 and 16 neutrons in the nucleus. The anion derived from the isotope has 18 electrons. Write the chemical symbol for this anion.
Short Answer
Step by step solution
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Isotope
For example, in our original problem, the isotope of the nonmetallic element in question has a mass number of 31 and 16 neutrons. This means that despite having multiple isotopes, the element can still be identified by its specific number of neutrons in combination with its mass number.
Isotopes are important in various fields, including chemistry and physics, because they help in understanding the properties and behaviors of elements as well as their stability. It also plays a significant role in medical imaging and treatment.
Mass Number
In our example, the isotope has a mass number of 31, meaning there are 31 combined protons and neutrons. Since we know there are 16 neutrons, it allows us to calculate the number of protons by subtracting the number of neutrons from the mass number (31 - 16 = 15 protons).
Understanding the mass number is crucial as it helps in identifying the specific isotope of an element and distinguishes it from other isotopes of the same atom, which might have different neutron numbers.
Protons
In the case of this exercise, the element has 15 protons. By referring to the periodic table, we can match this atomic number to an element, which is phosphorus (P). The atomic number for an element can never change without changing the element itself, as it defines what the element actually is.
Protons are essential not only in defining the identity of the element but also contributing to its mass number along with neutrons.
Neutrons
In our specific example, the isotope has 16 neutrons. These neutrons help add to the mass number of 31, but do not affect the overall charge of the atom. Neutrons are crucial for the stability of the nucleus as they help to mediate the strong force between protons, which are positively charged and naturally repel each other.
The number of neutrons can vary even in the same element, which results in different isotopes. Thus, they are key in determining the particular isotope of an element.
Anion
In the situation described, the phosphorus atom gains three electrons to become an anion with 18 electrons total, while it has only 15 protons. This situation gives the phosphorus anion a charge of (-3), as it has three more electrons than protons.
- Anions are critical in various chemical and biological processes, such as conductivity in solutions, and formation of salts.
- They are represented by adding a superscript to the element’s chemical symbol indicating their charge, e.g., (P^{3-}) for the example in this exercise.