MCQ On Elements And Atomic Structure! Trivia Quiz

The atomic number is the number of protons in an atom's nucleus. It determines the element's identity and its position on the periodic table. The other options mentioned in the question, such as mass number, subscript, and electron number, are not equivalent to the atomic number. The mass number is the sum of protons and neutrons, the subscript indicates the number of atoms in a molecule, and the electron number refers to the number of electrons in an atom. Therefore, the correct answer is "Proton number."

Isotopes are atoms of the same element that have the same number of protons (atomic number), but different numbers of neutrons (mass number). This means that isotopes have the same chemical properties but differ in their atomic mass. Therefore, the statement that isotopes have the same atomic numbers but different mass numbers is true.

The statement is true because the mass number of an atom represents the total number of protons and neutrons in its nucleus, while the atomic number represents the number of protons. By subtracting the atomic number from the mass number, we can determine the number of neutrons.

The nucleus is the central part of an atom that contains protons and neutrons. Electrons, on the other hand, are found in the electron cloud surrounding the nucleus. Therefore, electrons are not found in the nucleus, making them the correct answer.

This statement is true because isotopes are variants of an element that have the same number of protons but different numbers of neutrons. The mass number represents the total number of protons and neutrons in the nucleus of an atom, and it is written as a superscript next to the element's chemical symbol. The atomic number represents the number of protons in the nucleus, and it is written as a subscript next to the element's chemical symbol. Therefore, this statement accurately describes how isotopes are represented.

The atomic mass of an element is not always a whole number. It is the average mass of all the isotopes of that element, taking into account their relative abundance. Isotopes are atoms of the same element with different numbers of neutrons, which can result in different atomic masses. Therefore, the atomic mass of an element can be a decimal number.

The volume of an atom consists mostly of empty space because the electrons, which are negatively charged particles, occupy a relatively large amount of space compared to the size of the nucleus. On the other hand, the mass of an atom is accounted for mostly by protons and neutrons, which are located in the nucleus. These particles have a much higher mass compared to electrons. Therefore, the correct answer is "empty space; protons and neutrons."

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. They do not differ in their number of electrons. The number of protons determines the element's identity, while the number of neutrons affects the atom's mass. Therefore, isotopes have the same number of protons and electrons but differ in their number of neutrons.

The statement is false because the nucleus of an atom is actually very small compared to the overall size of the atom. The nucleus is located at the center of the atom and contains protons and neutrons, which are responsible for most of the atom's mass. However, the volume of the nucleus is extremely small compared to the volume of the entire atom, which is mostly made up of the electron cloud surrounding the nucleus.

The mass number of an element is the sum of its protons and neutrons. Since the question only provides the mass number and does not specify the number of protons or neutrons, it is impossible to determine the element based solely on the given information.