Isotopes

Isotopes are atoms of the same element that have different

• principal chemical properties.

• masses.

• numbers of protons.

• number of electrons.

As the mass number of an element's isotopes of an element increases, the number of protons

• decreases.

• increases.

• remains the same.

• doubles each time the mass number increases.

The average atomic mass of an element is the average of the atomic masses of its

• naturally occurring isotopes.

• two most abundant isotopes.

• radioactive isotopes.

• artificial isotopes.

The average atomic mass of an element

• is the mass of its most abundant isotopes.

• may not equal the mass of any of its isotopes.

• cannot be calculated.

• always adds up to 100.

The atomic mass of an element listed in the periodic table is the

• average atomic mass.

• relative atomic mass of the most abundant isotope.

• relative atomic mass of the most abundant radioactive isotope.

• mass number of the least abundant isotope.

Carbon-14 (atomic number 6), the radioactive nuclide used in dating fossils, has

• 6 neutrons.

• 8 neutrons.

• 10 neutrons.

• 14 neutrons.

What does the number 84 in krypton-84 represent?

• the atomic number

• the mass number

• the sum of the protons and electrons

• twice the number of protons

How do the isotopes of hydrogen-1 and hydrogen-2 differ?

• Hydrogen-2 has one more electron than hydrogen-1.

• Hydrogen-2 has one neutron, hydrogen-1 has none.

• Hydrogen-2 has two protons; hydrogen-1 has one.

• Hydrogen-2 has one proton; hydrogen-1 has none.

Tags

NGSS.HS-PS1-8

What unit is used to measure weighted atomic mass?

• amu

• gram

• angstrom

• nanogram

Which of the following equals one atomic mass unit?

• the mass of one electron

• the mass of one helium-4 atom

• the mass of one carbon-12 atom

• one-twelfth the mass of one carbon-12 atom