Isotopes and Atoms

Atoms are neutral because

• they have the same number of protons and electrons.

• they have the more protons than electrons.

• they have the more electrons than neutrons.

• they have the more electrons than protons.

What does the mass number tell you?

• The mass of the atom.

• The number of protons in the nucleus.

• The number of neutrons in the nucleus.

• The number of neutrons and protons in the nucleus.

What does the atomic number tell you?

• The mass of the atom.

• The number of protons in the nucleus.

• The number of neutrons in the nucleus.

• The number of neutrons and protons in the nucleus.

All atoms of chlorine have how many protons in their nuclei?

• 16

• 17

• 35

• 35.45

All atoms of uranium have how many protons in their nuclei?

The most common isotope of the element uranium is uranium-238. How many protons are there in each atom of this isotope?

• 146

• 238

• 92

• 145

The most common isotope of the element uranium is uranium-238. How many electrons are there in each neutral atom of this isotope?

• 146

• 238

• 92

• 145

Uranium is named after the Greek god of the sky. A planet is also named after the same god. Who is the Greek god?

Atoms of this element have how many protons in their nuclei?

Atoms of this isotope have how many protons in their nuclei?