Understanding Atoms and the Periodic Table

What are the three main subatomic particles that make up an atom?

• Neutrons, quarks, and photons

• Protons, neutrons, and photons

• Protons, neutrons, and electrons

• Electrons, photons, and quarks

What determines the atomic number of an element?

• The number of electrons

• The number of neutrons

• The number of protons

• The number of isotopes

What is the role of neutrons in an atom?

• To form chemical bonds

• To determine the atomic number

• To stabilize the nucleus by overcoming proton repulsion

• To balance the charge of electrons

How many electrons can the first electron shell hold?

• Eight

• Six

• Four

• Two

What are valence electrons?

• Electrons in the innermost shell

• Electrons that are shared between atoms

• Electrons that have no energy

• Electrons in the outermost shell that determine chemical properties

Which element starts the third period in the periodic table?

• Sodium

• Beryllium

• Lithium

• Magnesium

What do elements in the same group of the periodic table have in common?

• The same number of valence electrons

• The same atomic mass

• The same atomic number

• The same number of electron shells

How does the number of valence electrons change across a period?

• It decreases

• It remains the same

• It fluctuates randomly

• It increases

What trend is observed in the periodic table as you move down a group?

• Decreasing atomic number

• Increasing electron shells

• Decreasing electron shells

• Increasing valence electrons

What is the main factor that affects how atoms behave chemically?

• The atomic mass

• The number of neutrons

• The number of protons

• The arrangement of electrons