How is it possible that the atomic number increases in order, yet the atomic masses do not?
A. There is no relationship between the atomic number and mass of the atom.
B. The masses of the protons for Te, I, and Xe have slightly different masses.
C. Since the numbers of neutrons do not necessarily increase from one atom to the next, it is possible for the atomic number to increase while the total mass does not increase.
D. A and B are both correct.
E. B and C are both correct.
The correct answer is E. B and C are both correct.
In the periodic table, elements are arranged in order of increasing atomic number, which represents the number of protons present in the nucleus of an atom. Each element has a unique atomic number that determines its position in the periodic table.
However, the atomic mass of an atom is the total mass of the protons, neutrons, and electrons present. The atomic mass is not necessarily directly related to the atomic number.
Option B is correct because although the atomic number increases in order, the masses of the protons for elements like Te (Tellurium), I (Iodine), and Xe (Xenon) have slight differences. This is due to isotopes, which are atoms of the same element that have different numbers of neutrons. Isotopes have slightly different atomic masses, which can cause variations in the atomic mass even when the atomic number increases.
Option C is correct because the number of neutrons in an atom can vary within a particular element. Different isotopes of the same element will have different numbers of neutrons. This means that even though the atomic number increases, the total mass may not necessarily increase if the number of neutrons in the nucleus remains the same or changes only slightly.
Therefore, it is possible for the atomic number to increase while the atomic masses do not due to variations in the masses of the protons (option B) and the presence of different isotopes with different numbers of neutrons (option C).
The correct answer is E. B and C are both correct.
Explanation:
The atomic number of an atom is determined by the number of protons in its nucleus, which increases in order as you move from left to right across the periodic table. This is because the elements in the periodic table are organized based on increasing atomic number.
However, the atomic mass of an atom is determined by the sum of protons and neutrons in the nucleus. The masses of the protons for isotopes of an element can vary slightly due to the presence of different number of neutrons in their nuclei. For example, Te (tellurium), I (iodine), and Xe (xenon) have different isotopes with slightly different masses. So, even though the atomic number is increasing, the atomic mass may not always increase in a strict linear manner.
Additionally, the number of neutrons in the nucleus can vary among different isotopes of the same element. Isotopes are atoms of the same element with the same number of protons but a different number of neutrons. Since the atomic mass is the sum of protons and neutrons, if different isotopes of an element have different numbers of neutrons, the atomic mass can vary without a strict correlation with the atomic number.
Therefore, both factors, slightly different masses of isotopes and the variability of the number of neutrons, contribute to the phenomenon where the atomic number increases in order but the atomic masses may not strictly increase.