What does the atomic number (Z) represent for an element?

• The total number of protons and neutrons.

• The average mass of all isotopes of the element.

• The number of protons in the nucleus.

• The number of electrons in the outermost shell.

How does the atomic number (Z) help identify an element?

• It determines the element's chemical reactivity.

• It is unique to each element and defines its identity.

• It indicates the element's physical state at room temperature.

• It shows the element's position in a chemical group.

What is the term for atoms of the same element that have the same number of protons but different numbers of neutrons?

• Ions

• Allotropes

• Isotopes

• Isomers

What is the mass number (A) of an atom?

• The number of protons only.

• The number of neutrons only.

• The sum of protons and neutrons.

• The sum of protons, neutrons, and electrons.

The average atomic mass of Nitrogen is 14.01. Given that Nitrogen has isotopes Nitrogen-14 and Nitrogen-15, which isotope is more abundant?

• Nitrogen-14

• Nitrogen-15

• Both are equally abundant

• It cannot be determined from the given information.

For an atom of Boron (B) with an atomic number of 5, how many protons does it have?

• 10

• 11

• 5

• 10.81

If an element has an average atomic mass of 10.81 and its main isotopes are Boron-10 and Boron-11, which isotope is more prevalent in nature?

• Boron-10

• Boron-11

• Both are found in equal amounts.

• The abundance cannot be determined without knowing the exact percentages.

What is the net electric charge of a neutral atom?

• Positive, due to protons.

• Negative, due to electrons.

• Zero, because the number of protons equals the number of electrons.

• Variable, depending on the element's reactivity.

What is the atomic number of an element with 6 protons?

• 6

• 7

• 12

• 13

An element has an atomic number of 6. What is the identity of this element?

• Oxygen

• Nitrogen

• Carbon

• Boron