Understanding Isotopes

What defines an isotope of an element?

• Same number of electrons, different protons

• Same number of protons, different neutrons

• Same number of neutrons, different electrons

• Same number of protons, different electrons

How can you identify hydrogen as an element?

• By counting the number of neutrons

• By counting the number of electrons

• By counting the number of protons

• By counting the number of atoms

What is the mass number of a helium isotope with two protons and three neutrons?

• 8

• 7

• 6

• 5

How many neutrons does lithium-7 have if it has three protons?

• 6

• 5

• 4

• 3

What is the atomic number of chlorine if it has 17 protons?

• 19

• 18

• 17

• 16

How many neutrons are in carbon-14 if it has six protons?

• 6

• 7

• 8

• 9

Which of the following is NOT a criterion for isotopes?

• Same element

• Different number of neutrons

• Same number of protons

• Same number of electrons

In a fictitious element R, if one isotope has a mass number of 21 and another has 20, what can be inferred?

• They are different elements

• They have different numbers of protons

• They have different numbers of neutrons

• They have different numbers of electrons

What is the mass number of an isotope with five protons and eleven neutrons?

• 15

• 16

• 17

• 18

Which of the following elements can have isotopes?

• Only elements with an even number of protons

• Only hydrogen

• Only elements with more than one proton

• Any element