Isotope, one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behaviour but with different atomic masses and physical properties. Every chemical element has one or more isotopes. The elements with the most isotopes are cesium and Xenon with 36 known isotopes. Some isotopes are stable and some are unstable. When an isotope is unstable it will decay over time and eventually it will turn into another isotope or element.
1. Isotopes of an element have nuclei with ______.
a. a different number of protons, and a different number of neutrons.
b. the same number of protons, and the same number of neutrons.
c. the same number of protons, but different numbers of neutrons.
d. a different number of protons, and the same number of neutrons.
2. How many isotopes does H has?
a. 2
b. 4
c. 5
d. 3
3. Name the isotope with atomic number 92.
a. Ca
b. U
c. Rd
d. H
4. What are radioactive isotopes?
a. Any of several species of the same chemical element with different masses whose nuclei are unstable
b. Any of several species of the same chemical element with same masses whose nuclei are unstable
c. Any of several species of the same chemical element with different masses whose nuclei are stable
d. Any of several species of the same chemical element with same masses whose nuclei are stable
5. Heavier isotopes tend to react more slowly than lighter isotopes of the same element. State true or false.
a. TRUE
b. FALSE
