Unit Test

How many neutrons does the isotope of lithium have?

• 8
• 3
• 5

How many protons does this isotope of titanium have?

• 48
• 22
• 26

If a sulfur atom has 16 protons, 16 electrons, and 16 neutrons, its atomic mass is:

• 16
• 32
• 48

How is carbon-12 different from carbon-14?

• They have a different number of protons
• they have a different number of electrons
• they have a different number of neutrons

How many neutrons are in the isotope of sulfur,³⁶S?

• 16

• 20

• 24

• 26

How many neutrons are in the following atom?

• 47

• 61

• 108

• 155

An atom is electrically neutral when

• protons and neutrons are the same
• protons and electrons are the same
• neutrons and electrons are the same

Which of these determines the identity of an atom?

• proton

• neutron

• valence electron

• protons and neutrons

What is a mass number?

• The average atomic mass
• the number of protons and neutrons in the nucleus
• the number of protons in the nucleus
• the number of protons and electrons in the nucleus

How many electrons are in a neutral atom of the isotope fluorine-20?

• 20

• 9

• 19

• 18