Each atom of an element has the following electron configuration: [tex]$1 s^2 2 s^2 2 p^6 3 s^2 3 p^6 4 s^2 3 d^{10} 4 p^6 5 s^2 4 d^{10} 5 p^5$[/tex]
What is the name of the element?
A. bromine
B. iodine
C. tellurium
D. xenon
Answer (1)
Count the total number of electrons from the electron configuration: 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 10 + 5 = 53 .
Recognize that the number of electrons equals the atomic number of the element.
Identify the element with atomic number 53 on the periodic table.
Conclude that the element is i o d in e .
Explanation
Understanding the Problem We are given the electron configuration of an element: 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 10 4 p 6 5 s 2 4 d 10 5 p 5 . Our task is to identify the element based on this configuration.
Calculating the Total Number of Electrons To identify the element, we need to determine the total number of electrons, which is equal to the element's atomic number. We sum the superscripts in the electron configuration: 2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 10 + 5 = 53 .
Identifying the Element The element with atomic number 53 is iodine (I).
Conclusion Therefore, the element is iodine.
Examples
Understanding electron configurations helps us predict how elements will interact with each other to form chemical compounds. For example, knowing that iodine has 53 electrons and its outermost shell has 7 electrons allows us to understand its tendency to gain one electron to form stable compounds like sodium iodide (NaI), which is used in table salt and as a dietary supplement.
