Chapter 2: Atomic Structure

• What did Aristotle believe the four elements were?

  Earth, air, fire, and water.
• Democritus – argued all matter at the most fundamental level wascomposed of small, finite particles called “atomos”
• When was the first proof of atomic theory?

  early 1800s
• Who was John Dalton?

  John Dalton was an English chemist, physicist, and meteorologist who is best known for his work on atomic theory.
• What were the 5 parts of Dalton's theory?

  1.Matter is composed entirely of small particles called atoms. They are the smallest unit of matter that can participate in chemical change.

  2. Every atom of a given element behaves exactly the same as each other.

  3. Atoms of different elements have different properties

  4. The number of atoms of different elements in a compound exist in simple whole number ratios

  5. Atoms are not created or destroyed, but only rearranged in a reaction.
• Who discovered the electron and how did he do it?

  J.J. Thomson; through cathode ray tube experiments[cathode rays are used in old TVs].
• What is the plum pudding model?

  The plum pudding model was a model of the atom proposed by J.J. Thomson, which suggested that the atom was composed of positive and negative charges scattered throughout, similar to plums in a pudding.
• Who is Robert Millikan and what did he discover?

  Robert Millikan was an American physicist who discovered the charge of an electron through his famous oil drop experiment in 1909.
• Who discovered the nucleus and how?

  Ernest Rutherford, through his gold foil experiment in 1911.
• What are the two molecules in the nucleus?

  Protons(+) and neutrons(0).
• What is an isotope?

  An isotope is a variant of an element that has the same number of protons but a different number of neutrons in its nucleus.
• How many protons, neutrons, and electrons in 88 Sr^2+ ?

  38 protons, 50 neutrons and 36 electrons
• How many protons,neutrons andelectrons are in F^-1 ?

  9 protons, 9 neutrons, 10 electrons