Atoms and the Periodic Table

the smallest unit of an element that maintains the properties of the element.

• atom

• neutron

• electron

• atomic number

a unit of mass that describes the mass of an atom or molecule.

• atomic mass unit

• electron

• neutron

• isotope

Tags

NGSS.HS-PS1-7

the number of protons in the nucleus of an atom; the __________ is the same for all atoms of an elements.

• atomic number

• nucleus

• proton

• electron

a subatomic particle that has a negative charge.

• electron

• atomic number

• proton

• atomic mass unit

an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass.)

• isotope

• atom

• proton

• neutron

a subatomic particle that has no charge and that is located in the nucleus of an atom.

• neutron

• atomic mass unit

• atomic number

• isotope

an atom's central region that is made up of protons and neutrons.

• nucleus

• isotope

• atom

• electron

a subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of __________ in the nucleus is the atomic number, which determines the identity of an element.

• proton

• electron

• nucleus

• atomic mass unit

the mass of an atom expressed in atomic mass units.

• atomic mass

• atomic mass unit

• mass number

• atomic number

a region around the

nucleus of an atom where electrons are likely to be found.

• electron cloud

• noble gas

• nucleus

• isotope