Isotopes and Radioactivity

In a correctly written symbol what would be located in the "A" position?

• number of neutrons

• atomic number

• number of electrons 

• mass number

What quantities vary between isotopes of an element?

• protons, electrons, and atomic mass

• protons, electrons, and atomic number

• neutrons and electrons

• neutrons and atomic mass

How many neutrons does a Carbon 13 atom have?

• 6

• 5

• 7

• 8

Tags

NGSS.MS-PS1-1

How many neutrons does a Calcium 48 isotope have?

• 16

• 20

• 28

• 12

Which of the following defines the Mass number of an atom?

• number of protons + number of electrons

• number of neutrons + number of electrons

• number of protons + number of neutrons

• number of electrons

What do these isotopes of carbon all have in common?

• neutrons & mass number

• atomic number and neutrons

• atomic number and electrons

• protons, atomic number, and mass number

Tags

NGSS.MS-PS1-1

12 protons and 13 neutrons

• Mg-12

• Mg-13

• Mg-25

• Mg-24.305

Tags

NGSS.MS-PS1-1

What is radioactivity?

• A term that describes the forces that hold atomic nuclei together

• The movement of electrons around an atomic nucleus

• The application of heat energy to an atomic nucleus

• The emission of high-energy particles or waves from atoms

Tags

NGSS.HS-PS1-8

What is a half-life?

• The average time it takes for any element to disappear completely

• The time it takes for half of any number of radioactive atoms to decay

• The time it takes for a radioactive atom to lose half its neutrons

• The time it takes for a radioactive atom to lose half its electrons

Tags

NGSS.HS-PS1-8

Imagine you have 50,000 atoms of uranium-238. If U-238 has a half-life of 4.5 billion years, how many U-238 atoms will be left after 4.5 billion years?

• 25,000

• 50,000

• 12,500

• 0

Tags

NGSS.HS-PS1-8