2.1.1 Atomic structure

• Protons and neutrons make up the atom's mass.


  True
• Match the subatomic particle with its charge, location, and role:

  Protons ↔️ Positive, nucleus, determine element's identity

  Neutrons ↔️ Neutral, nucleus, stabilize nucleus

  Electrons ↔️ Negative, orbiting nucleus, chemical bonding
• Protons and neutrons form the nucleus of an atom.


  True
• Protons carry a positive charge
• Electrons are involved in chemical bonding and reactions.


  True
• Arrange the subatomic particles in order of increasing charge magnitude:

  1️⃣ Neutrons (0)

  2️⃣ Electrons (-1)

  3️⃣ Protons (+1)
• Neutrons contribute significantly to an atom's mass
• The atomic number of an element is determined by the number of protons.


  True
• What does the atomic number represent in an atom?

  Number of protons
• The atomic number determines the element's identity, while the mass number contributes to its atomic mass.


  True
• Electrons are responsible for chemical bonding
• Protons and neutrons have approximately the same relative mass.

  True
• Neutrons contribute to atomic mass and stabilize the nucleus
• Isotopes of an element have the same number of protons but a different number of neutrons.


  True
• A stable isotope like carbon-12 does not decay
• Match the shell number with its maximum number of electrons:

  1 ↔️ 2

  2 ↔️ 8

  3 ↔️ 18

  4 ↔️ 32
• What are the principal energy levels in an atom also called?

  Shells
• What do the principal energy levels, or shells, numbered 1 to 7 represent?

  Allowed energy states
• The maximum number of electrons in the first shell (n=1) is 2

  True
• How many electrons can the second shell (n=2) hold?

  8
• The maximum number of electrons per shell increases with higher shell numbers


  True
• The electron configuration of an atom affects its chemical behavior and reactivity.
• What is the fundamental unit of matter called?

  Atom
• Protons determine the identity of an element


  True
• What charge do protons carry?

  Positive
• Which subatomic particle has the highest relative mass?

  Protons
• Neutrons contribute significantly to an atom's mass


  True
• Electrons have a negative charge and contribute very little to atomic mass.
• The mass number is the total number of protons and neutrons in the nucleus.
• What is the main difference between isotopes of the same element?

  Number of neutrons
• Isotopes have the same number of protons


  True
• What are isotopes defined by?

  Same protons, different neutrons
• Isotopes of the same element have identical masses.

  False
• What happens to carbon-14 over time?

  Radioactive decay
• The innermost shell (n=1) can hold a maximum of two
• The maximum number of electrons in a shell is calculated by the formula 2n²
• Which sublevel can hold the most electrons?

  f sublevel
• Order the filling of orbitals by increasing energy level:

  1️⃣ 1s

  2️⃣ 2s

  3️⃣ 2p

  4️⃣ 3s

  5️⃣ 3p

  6️⃣ 4s

  7️⃣ 3d
• What is the basic unit of matter called?

  Atom
• The nucleus of an atom contains protons and neutrons