1.1.1 Understanding atoms as the smallest part of an element

• What surrounds the nucleus of an atom?

  Electrons in shells
• Give an example of a compound.

  Water (H₂O)
• How many electrons does an oxygen atom have?

  8
• Atoms can be broken down into smaller particles using normal chemical reactions.

  False
• How many neutrons are in an oxygen atom?

  8
• What are the smallest independent particles that make up elements?

  Atoms
• Hydrogen is the simplest atom with 1 proton and 1 electron.


  True
• How do the structures of an atom and a molecule differ?

  An atom has protons, neutrons and electrons, while a molecule is made up of two or more atoms bonded together
• What is an element in chemistry?

  A pure substance
• Match the term with its description:

  Atom ↔️ Smallest part of an element

  Molecule ↔️ Made of two or more atoms
• What is the smallest unit of matter that retains the chemical properties of an element?

  An atom
• What is the formula for calculating the area of a circle?

  $A =$$\pi r^2$
• Elements can be broken down into simpler substances by chemical means.

  False
• What is the name of the central part of an atom?

  Nucleus
• What atoms form a water molecule (H₂O)?

  One oxygen and two hydrogen
• How many protons are in an oxygen atom?

  8
• Why are atoms considered the smallest part of an element?

  They retain element characteristics
• What is the atomic number of oxygen?

  8
• What are the elements produced when water (H₂O) is broken down?

  Hydrogen and oxygen
• Where is the nucleus located in an atom?

  At the center
• How many electrons are in an oxygen atom?

  8
• A compound can be broken down into its elements by chemical means.


  True
• What are the components of a water (H2O) molecule?

  • 1 Oxygen atom
  • 2 Hydrogen atoms
• How does the stability of an atom compare to that of a molecule?

  Atoms are stable independently
• Electrons orbit the nucleus in circular tracks called electron shells


  True
• Arrange the following in order of decreasing size:

  1️⃣ Molecule

  2️⃣ Atom

  3️⃣ Subatomic particle
• What are the key components of an atom?

  • Protons
  • Neutrons
  • Electrons
• Atoms form molecules when they join together through chemical bonds


  True
• A water molecule (H₂O) is formed by one oxygen atom bonded with two hydrogen atoms


  True
• What are the main components of an atom?

  • Electron shell
  • Nucleus
  • Protons
  • Neutrons
• What is the name of the outermost layer of an atom?

  Electron shell
• What are the three subatomic particles in an atom?

  Proton, neutron, electron
• How do the masses of the main atomic particles compare?

  • Protons and neutrons have approximately the same mass
  • Electrons have a much smaller mass compared to protons and neutrons
• What are the key components of the Bohr atomic model?

  • Nucleus containing protons and neutrons
  • Electrons orbiting the nucleus in discrete energy levels or shells
  • Electrons can only occupy certain allowed energy levels
  • Electrons can jump between energy levels by absorbing or emitting photons
• All shells in an atom can hold the same number of electrons

  False
• How many electrons can each shell in an atom hold?

  A specific number
• The charge of a proton is positive.


  True
• The mass of an electron is approximately 0 amu.

  True
• How do the charges of the main atomic particles compare?

  • Protons have a positive charge
  • Electrons have a negative charge
  • Neutrons have no charge (are neutral)
• What is a molecule formed from two hydrogen atoms and one oxygen atom?

  Water molecule