C1.2.1 The Structure of an Atom

• What is the smallest unit of an element that retains its chemical properties?

  Atom
• Electrons have a relative mass of 1.

  False
• Electrons orbit the nucleus in specific energy levels known as electron shells
• What is the charge of a neutron?

  0
• Where do protons reside in an atom?

  Nucleus
• Match the subatomic particle with its properties:

  Protons ↔️ +1 charge, mass 1

  Neutrons ↔️ 0 charge, mass 1

  Electrons ↔️ -1 charge, negligible mass
• Protons and neutrons reside in the central nucleus
• Neutrons have a charge of -1.

  False
• The mass number is the total number of protons and neutrons
• What are isotopes of the same element defined as?

  Same protons, different neutrons
• Order the energy levels of an atom from closest to farthest from the nucleus:

  1️⃣ n=1

  2️⃣ n=2

  3️⃣ n=3

  4️⃣ n=4
• Protons and neutrons are located in the central core of the atom called the nucleus
• What is the charge of a proton?

  +1
• Neutrons have a negative charge.

  False
• Electrons have a charge of -1
• Electrons orbit the nucleus in fixed circular paths.


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

  Protons, neutrons, electrons
• Where are protons and neutrons located in an atom?

  Nucleus
• What is the atomic number of an element defined as?

  Number of protons
• Match the term with its definition:

  Atomic Number ↔️ Number of protons in the nucleus

  Mass Number ↔️ Total number of protons and neutrons
• Isotopes of the same element have identical physical and chemical properties.

  False
• What is the maximum number of electrons that the first energy level (n=1) can hold?

  2