Question

Which of the following elements represents an atom of calcium?

A) Element 1 - 20 protons, 20 neutrons, 20 electrons.
B) Element 2 - 40 protons, 40 neutrons, 40 electrons.
C) Element 3 - 20 protons, 10 neutrons, 10 electrons.
D) Element 4 - 20 protons, 20 neutrons, 40 electrons.

Answer 1

Element 1 - 20 protons, 20 neutrons, and 20 electrons option (a), represents an atom of calcium as it matches the atomic number and properties of a neutral calcium atom.

Step-by-step explanation:

In determining which of the options represents an atom of calcium, it is essential to know the attributes of calcium. Calcium, with an atomic number of 20, will have 20 protons in its atom. An atom is neutral when the number of electrons is equal to the number of protons. As such, a neutral calcium atom will have 20 electrons.

Regarding neutrons, the most common isotope of calcium has 20 neutrons (40 - 20 = 20), giving it a mass number of 40 (20 protons + 20 neutrons).

Therefore, the option that represents an atom of calcium is Element 1 - 20 protons, 20 neutrons, and 20 electrons. The number of protons determines the element type, and since calcium has 20 protons, Element 1 matches this description. Options B, C, and D do not correspond to the properties of a neutral calcium atom.