What does the number at the bottom of each element's box on the periodic table represent?

• The number of neutrons

• The atomic number

• The number of protons

• The average atomic mass

What are isotopes?

• Atoms of different elements with the same number of neutrons

• Atoms of different elements with the same number of protons

• Atoms of the same element with different numbers of neutrons

• Atoms of the same element with different numbers of protons

What does it mean for an isotope to be radioactive?

• It is found only in synthetic elements

• It has an unstable nucleus that loses mass over time

• It has more protons than neutrons

• It has more electrons than protons

Tags

NGSS.HS-PS1-8

Which isotope of hydrogen has no neutrons?

• Protium

• Hydrogen-2

• Deuterium

• Tritium

How many neutrons does deuterium have?

• 2

• 1

• 3

• 0

What is the mass number of tritium?

• 1

• 2

• 3

• 4

How many protons are in carbon-12?

• 12

• 6

• 7

• 8

What is the mass number of carbon-14?

• 14

• 15

• 13

• 12

How many neutrons are in carbon-13?

• 6

• 7

• 8

• 13

If an atom has 19 protons and 22 neutrons, what is its mass number?

• 41

• 22

• 43

• 19