ATOMIC STRUCTURE

• The size of an atom is approximately 0.1 nanometers.
• What does the word "atom" mean according to the Greeks?

  Uncuttable
• What is the charge of a proton?

  +1
• The atomic number of an element is equal to the number of protons in its nucleus.

  True
• Protons and neutrons are located in the nucleus of an atom.


  True
• The mass of an electron is approximately 1/1836 of a proton's mass.
• How do you calculate the number of neutrons in an atom?

  Mass number - atomic number
• An atom with the same number of protons and electrons has no overall charge.

  True
• Steps to calculate the number of protons, neutrons, and electrons in boron-11

  1️⃣ Find the atomic number (5) from the periodic table.

  2️⃣ Determine the number of protons (5) and electrons (5).

  3️⃣ Calculate the number of neutrons (11 - 5 = 6).
• What is an ion?

  An atom that has lost or gained electrons
• Isotopes of an element have the same number of protons but a different number of neutrons.
• Match the atomic model with its key development:

  Dalton ↔️ Solid sphere model

  J.J. Thomson ↔️ Plum pudding model

  Rutherford ↔️ Nuclear model
• Timeline of atomic model developments

  1️⃣ Dalton's solid sphere model

  2️⃣ Thomson's plum pudding model

  3️⃣ Rutherford's nuclear model

  4️⃣ Chadwick's discovery of neutrons

  5️⃣ Bohr's improved nuclear model
• Rutherford's gold foil experiment proved that the atom is mostly empty space.


  True
• Match the type of radiation with its properties:

  Alpha radiation ↔️ Highly ionizing, low penetrating

  Beta radiation ↔️ Moderately ionizing, moderately penetrating

  Gamma radiation ↔️ Low ionizing, highly penetrating
• Different isotopes of an element have the same half-life.

  False
• What is beta radiation made of?

  Electrons
• Steps to calculate half-life from a decay graph

  1️⃣ Identify two points on the graph where the activity is reduced by half.

  2️⃣ Measure the time interval between these two points.

  3️⃣ The time interval is the half-life.
• What is the main source of background radiation?

  Radon gas
• Steps in a chain reaction during nuclear fission

  1️⃣ A neutron hits a radioactive nucleus.

  2️⃣ The nucleus splits, releasing energy, neutrons, and radiation.

  3️⃣ The released neutrons hit other nuclei, continuing the reaction.
• Gamma radiation is used in medicine for cancer treatment.
• Nuclear fusion releases energy in the form of light, heat, or sound.

  True