Question

What element is defined by the following information? (Refer to the periodic table above.) p+=20 n°=20 e−=20

A) Calcium (Ca)
B) Argon (Ar)
C) Neon (Ne)
D) Magnesium (Mg)

Answer 1

The element with 20 protons, 20 neutrons, and 20 electrons is Calcium (Ca). Its atomic number is 20, which fits the given criteria, making it the correct answer.

Step-by-step explanation:

The element defined by having 20 protons (p+), 20 neutrons (n°), and 20 electrons (e−) is Calcium (Ca). The number of protons, which is 20 in this case, determines the identity of the element on the periodic table; that number is known as the atomic number. Since Calcium has an atomic number of 20, it matches the element described. Additional information that supports this identification includes an understanding of isotope notation (Americium-241 would be represented as ^{241}Am) and the general electron configurations, which are useful for denoting the arrangement of electrons around the nucleus of atoms, such as the electron configuration of Calcium being [Ar]4s² or that of Magnesium being [Ne]3s².