Unit 1: Atomic Structure Test

The nucleus of an atom has all of the following characteristics except that it

• is very dense.

• contains protons and neutrons.

• is positively charged.

• contains almost all of the atom’s volume.

What makes an atom electrically neutral?

• The neutrons balance out the protons and electrons.

• The nuclear forces contained in the atom neutralize the atom.

• The number of protons is equal to the number of electrons.

• The number of protons is equal to the number of neutrons.

The smallest particle of an element that retains the properties of that element is a(n)

• electron

• atom

• proton

• quark

What does the number 91 represent in the name zirconium-91?

• the atomic number

• the number of protons

• the mass number

• the sum of protons and electrons

An element has an atomic number of 72. The number of protons and electrons in a neutral atom of this element is

• 72 protons and 72 electrons

• 72 protons and 0 electrons

• 36 protons and 36 electrons

• none of the above

Which of the following sets is correct?

• Zn-65, 65 protons, 65 electrons

• Mg-24, 12 protons, 12 neutrons

• U-238, 92 protons, 92 neutrons

• Pb-207, 207 protons, 207 electrons

An atom has an atomic number of 32 and a mass number of 73. How many protons, neutrons, and electrons does

this atom contain?

• 32 protons, 73 neutrons, 32 electrons

• 73 protons, 73 neutrons, 41 electrons

• 32 protons, 41 neutrons, 32 electrons

• 41 protons, 32 neutrons, 41 electrons

Identify the element that has 31 neutrons and a mass of 59.

• gallium

• praseodymium

• thorium

• nickel

Isotopes of the same element have different

• chemical properties.

• masses.

• atomic numbers.

• number of protons.

All atoms of the same element have the same

• number of protons.

• mass number.

• number of neutrons.

• protons and neutrons.