Fall Final (chem)

An atom that has an electric charge is called a(n)

• isotope

• ion

• molecule

• compound

Two isotopes of an element have different

• number of neutrons

• number of protons

• number of electrons

• mass numbers

• two of these choices are correct

The atomic number of uranium is 92. How many protons, electrons and neutrons (in that order) are in a neutral atom of uranium-235?

• 92, 92, 143

• 143, 143, 92

• 235, 235, 92

• 92, 92, 235

The number of protons in an atom's nucleus is called its

• atomic radius

• atomic number

• mass number

• charge

A chemical change must produce

• a gas

• a mixture

• a new substance

• the same substance

Iron (Fe) has a charge of 3⁺. Oxygen (O) has a charge of 2^-. What is the chemical formula when iron reacts with oxygen?

• Fe₂O₃

• Fe₃O₂

• O₂Fe₃

• O₃Fe₂

Calcium (Ca) has a charge of 2⁺. Sulfur (S) has a charge of 2^-. What is the chemical formula when calcium reacts with sulfur?

• CaS

• Ca₁S₁

• Ca₂S₂

• SCa

True or false: matter expands when cooled.

• true

• false

An aluminum atom has 13 protons in its nucleus. If this atom has a charge of 3⁺, how many electrons are present?

• 3

• 7

• 10

• 13

How many "3d" electrons does copper (Cu) contain?

• 7

• 8

• 9

• 29