part 2: interpreting the evidence\n1. which evidence supports the existence of each atomic part…

part 2: interpreting the evidence\n1. which evidence supports the existence of each atomic part? explain.\na. negatively charged particles\nb. a nucleus\n2. examine the information and evidence in part i. in what order do you suppose these models were introduced to the world of science?\n3. in 1932, british physicist james chadwick discovered that the nucleus was made up of uncharged, or neutral, particles called neutrons, in addition to the protons discovered by rutherford. how do the three small particles found in the atom differ from one another?\n4. a helium atom has two electrons, two protons, and two neutrons.\na. how many positive charges does the helium atom have?\nb. how many negative charges does the helium atom have?\nc. what is the charge on the helium atom? explain your reasoning.\n5. making sense construct the best model of the atom you can. use all the evidence given previously.\n6. if you finish early atoms are not flat. how can you revise the model you constructed in the making sense exercise to account for this evidence?

part 2: interpreting the evidence\n1. which evidence supports the existence of each atomic part? explain.\na. negatively charged particles\nb. a nucleus\n2. examine the information and evidence in part i. in what order do you suppose these models were introduced to the world of science?\n3. in 1932, british physicist james chadwick discovered that the nucleus was made up of uncharged, or neutral, particles called neutrons, in addition to the protons discovered by rutherford. how do the three small particles found in the atom differ from one another?\n4. a helium atom has two electrons, two protons, and two neutrons.\na. how many positive charges does the helium atom have?\nb. how many negative charges does the helium atom have?\nc. what is the charge on the helium atom? explain your reasoning.\n5. making sense construct the best model of the atom you can. use all the evidence given previously.\n6. if you finish early atoms are not flat. how can you revise the model you constructed in the making sense exercise to account for this evidence?

Answer

Explanation:

Step1: Evidence for negatively - charged particles

The cathode - ray tube experiment provided evidence for negatively - charged particles (electrons). When a high voltage is applied across the electrodes in a cathode - ray tube, a beam of particles is emitted from the cathode. These particles are deflected by electric and magnetic fields in a way that indicates they are negatively charged.

Step2: Evidence for a nucleus

The gold - foil experiment by Rutherford provided evidence for a nucleus. When alpha particles were fired at a thin gold foil, most of the particles passed straight through, but a small number were deflected at large angles. This indicated that most of the mass and positive charge of the atom is concentrated in a small, dense nucleus.

Step3: Order of atomic models

The order of atomic models is generally: Dalton's solid - sphere model (simple, indivisible atoms), Thomson's plum - pudding model (electrons embedded in a positive sphere), Rutherford's nuclear model (nucleus with electrons orbiting), Bohr's model (electrons in specific orbits around the nucleus).

Step4: Differences between atomic particles

Protons are positively charged, electrons are negatively charged, and neutrons are neutral. Protons and neutrons are found in the nucleus and have relatively large mass compared to electrons. Electrons are outside the nucleus and have a much smaller mass.

Step5: Charges in helium atom

a. A helium atom has 2 protons, so it has 2 positive charges. b. A helium atom has 2 electrons, so it has 2 negative charges. c. The charge on the helium atom is 0. Reasoning: The number of positive charges (2 protons) equals the number of negative charges (2 electrons), so the atom is electrically neutral.

Step6: Atomic model construction

Based on the evidence, a good model of the atom has a small, dense nucleus containing protons and neutrons, with electrons orbiting the nucleus in specific energy levels.

Step7: Revising atomic model for non - flat atoms

To account for atoms not being flat, a three - dimensional model of the atom should be constructed. For example, electrons can be thought of as existing in a three - dimensional electron cloud around the nucleus.

Answer:

  1. a. Cathode - ray tube experiment shows negatively - charged particles (electrons) are emitted from the cathode and are deflected by electric and magnetic fields. b. Rutherford's gold - foil experiment: most alpha particles pass through, some are deflected, indicating a small, dense, positively - charged nucleus.
  2. Dalton's solid - sphere model, Thomson's plum - pudding model, Rutherford's nuclear model, Bohr's model.
  3. Protons are positive, electrons are negative, neutrons are neutral. Protons and neutrons in nucleus, electrons outside nucleus; protons and neutrons have large mass, electrons have small mass.
  4. a. 2 positive charges. b. 2 negative charges. c. 0 charge; equal number of protons and electrons makes it neutral.
  5. Nucleus with protons and neutrons, electrons orbiting in energy levels.
  6. Construct a three - dimensional model with an electron cloud around the nucleus.