Radioactivity Unit Test remediation

All isotopes with an atomic number (number of protons) over 82 are ______________________.

• metalloids
• radioactive
• nonmetals
• always stabel

Which of the following statements is TRUE about nuclear fission and nuclear fusion reactions?

• Nuclei split during fission and combine during fusion.
• Fission forms heavier elements, and fusion forms lighter elements.
• Fission generates potential energy, and fusion generates kinetic energy.
• Nuclei gain electrons during fission and release electrons during fusion.

If Uranium (U) has an atomic number of 92, then how many neutrons are in the isotope U-238?

• 92
• 330
• 146
• 238

The process in which an atom loses particles and becomes another element is known as _______________.

• fusion
• fission
• transmutation
• chain reaction

Atoms of the same element with different numbers of neutrons are called _________________.

• isotopes
• metals
• metalloids
• radioactive elements

Which statement is NOT true about all the isotopes of an element?

• They have the same number of protons.
• They have different number of neutrons.
• They have the same atomic number.
• They have the same mass number.

A certain atom has 20 protons, 20 electrons, and 29 neutrons. Its mass number is _______.

• 20
• 40
• 29
• 49

Thorium-234 has a half life of 24 days. If you started with a 100 gram sample of Thorium-234, how much would remain after 48 days?

• 50 grams
• 25 grams
• 12.5 grams
• 100 grams

The stability of a nucleus depends on the _____________.

• atomic mass
• atomic number
• proton-neutron ratio
• number of neutrons

Which two elements are MOST commonly involved in nuclear fusion reactions?

• Hydrogen (H) and Uranium (U)
• Helium (He) and Uranium (U)
• Hydrogen (H) and Krypton (Kr)
• Hydrogen (H) and Helium (He)