2.3.1 Atomic Structure

• Electrons orbit the nucleus in shells
• Atoms are composed of three key subatomic particles
• What does the mass number of an atom represent?

  Protons and neutrons
• The mass number of an atom is the total number of protons and neutrons.
• The atomic number of an element determines its chemical properties.
• What is the fundamental unit of matter that makes up all substances called?

  Atom
• Electrons orbit the nucleus in shells
• The mass number is calculated by adding the number of protons and neutrons in the nucleus.
• The first electron shell can hold up to 2 electrons.
• Protons and neutrons are both found in the nucleus of an atom.
• Arrange the subatomic particles in order based on their location within the atom:

  1️⃣ Protons in the nucleus

  2️⃣ Neutrons in the nucleus

  3️⃣ Electrons orbiting the nucleus
• What is the charge of a neutron?

  Neutral
• Electrons contribute most to the atom's mass.

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

  Number of protons
• The relative abundance of isotopes refers to the percentage of each isotope in a natural sample
• What is the fundamental unit of matter that makes up all substances?

  Atom
• Match the subatomic particle with its charge:

  Protons ↔️ Positive

  Neutrons ↔️ Neutral

  Electrons ↔️ Negative
• The charge of an electron is negative
• Neutrons are neutral particles located in the nucleus of an atom.
• The mass number is calculated by adding the number of protons and neutrons
• Protons are positively charged particles located in the nucleus
• The innermost electron shell can hold up to 2 electrons.
• What are isotopes of the same element defined as?

  Same protons, different neutrons
• Protons are positively charged and located in the nucleus of an atom.
• The atomic number of an atom represents the number of protons in the nucleus.
• What is the atomic number of an atom equal to?

  Number of protons
• How many electrons can the innermost shell of an atom hold?

  2
• The mass number of an atom is always greater than or equal to its atomic number.
• Where do protons and neutrons reside in the atom?

  Nucleus
• The mass number of an atom is the total number of protons and neutrons
• What two subatomic particles are located in the nucleus of an atom?

  Protons and neutrons