Isotopes of the same element have similar chemical properties because they have the same number of

Step 1: Analyze the question The question asks why isotopes of the same element behave alike chemically. It asks which particle count they share.

Step 2: Explain the concept

• Isotopes are atoms of the same element with the same atomic number but different mass numbers.
• The atomic number is the number of protons. In a neutral atom, it also equals the number of electrons.
• Chemical properties depend on how an atom gains, loses, or shares electrons. This is determined by the electron arrangement, which is fixed by the number of protons (the nuclear charge).
• Neutrons carry no charge and do not affect electron arrangement. They only change the mass, so they affect physical properties such as density and mass, not chemical behaviour.

Step 3: Solution

• A. Nuclides: a nuclide is a type of atom defined by its specific proton and neutron numbers. Isotopes are different nuclides, so this is wrong.
• B. Protons: isotopes have the same number of protons. This fixes the electronic configuration and therefore the chemical properties. Correct.
• C. Neutrons: this is what makes isotopes different, so it is wrong.
• D. Atoms: this is not a particle count that explains the similarity, so it is wrong.

Step 4: Answer The correct option is B. protons.

Step 5: Exam tip Remember: "Same protons = same element = same chemistry. Different neutrons = different mass." Whenever WASSCE, JAMB, or NECO asks why isotopes have the same chemical properties, think of protons and electrons. When it asks why their physical properties differ, think of neutrons and mass number.