Atomic Structure

What is the smallest unit of matter? It is composed of protons and neutrons, held together in the nucleus, and electrons around the nucleus in different electron orbitals, which form an electron cloud.

• cell

• nucleus

• atom

• electron

What are any of the various self-contained units of matter or energy that are fundamental parts of all matter. These particles include electrons, protons, and neutrons.

• subatomic particles

• elements

• nucleus

• electron cloud

What is a subatomic particle with a positive charge that is in the nucleus of an atom?

• neutron

• proton

• electron

• valence electron

What is a subatomic particle without an electric charge, located in the nucleus of an atom?

• neutron

• proton

• electron

• valence electron

What is a subatomic particle with a negative charge? It is found in the electron cloud surrounding the nucleus.

• neutron

• proton

• electron

• electron cloud

What is the system of electrons surrounding the nucleus of an atom?

• valence electrons

• nucleus

• electrons

• electron cloud

What is the center of an atom containing protons and neutrons?

• nucleus

• neutron

• proton

• electron cloud

What is the number of protons in the nucleus of an atom that determines the chemical properties of an atom?

• mass number

• atomic mass

• atomic number

• atomic symbol

What is the combined mass of all the protons and neutrons of an atom and is approximately equal to the number of protons and neutrons?

• atomic mass

• atomic number

• subatomic particles

• nucleus weight

What is the atomic number?

• the number of protons in the nucleus

• the number of protons and neutrons in the nucleus

• the number of neutrons in the nucleus

• the number of protons in the energy levels