Atomic Structure

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

Most of the mass in an atom is made up of _____________________?

• protons and electrons
• protons and neutrons
• neutrons and electrons
• electrons and quarks

Where is most of the mass in an atom located?

• in the nucleus
• in the protons
• in the neutrons
• in the electrons

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 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

A section of the Periodic Table of Elements is provided. What is the chemical symbol for magnesium?

• 12
• Mg
• 24.31
• Magnesium