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 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 center of an atom containing protons and neutrons?

• nucleus

• neutron

• proton

• electron cloud

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

The number 16 for the atomic element sulfur is the

• ionic number

• isotope

• atomic mass

• atomic number

How many protons does sulfur have?

• 32

• 16

• 48

• 12

How many electrons does sulfur have

• 16

• 32

• 48

• 12

In an atom, the number of protons is equal to the number of ____________.

• energy levels

• neutrons

• neurons

• electrons