Unit 4: Atom Vocabulary

a dense, positively charged mass located in the center of the atom

• nucleus

• proton

• neutron

a positively charged subatomic particle that is found in the nucleus of an atom

• proton

• nucleus

• neutron

a negatively charged subatomic particle that is found in the space outside the nucleus

• electron

• proton

• atom

a neutral subatomic particle that is found in the nucleus of an atom

• neutron

• atom

• proton

the number of protons in an atoms of that element

• atomic number

• proton

• nucleus

the sum of protons and neutrons in the nucleus of an atom

• mass number

• protons

• atom

atoms of the same element that have different numbers of neutrons and different mass numbers

• isotopes

• protons

• neutrons

the possible energies that electrons in an atom can have

• energy levels

• atoms

• neutrons

a visual model of the most likely locations for electrons in an atom

• electron cloud

• atom

• isotopes

a region of space around the nucleus where an electron is likely to be found

• orbital

• atom

• neutron