District 1 - Atomic Theory

Welcome to your training for how to take down District 1 when you are in the arena. This is a district that is known to be quick cocky due to the fact that they know that they are fundamental to existence of all other Districts. They are well advised by past champions Rutherford, Thomson and Bohr.

Beware if you are to do battle with this District, stray electrons have killed many tributes in past Hunger Games.

Past District 1 Champions

  • J.J. Thomson
  • Ernest Rutherford
  • Niels Bohr

Our Friend the Atom

Please take out your District 1 guided notes and review the following content:

Parts of the Atom:

There are three subatomic particles that exist within the atom:

  1. Protons
  2. Neutrons
  3. Electrons

Protons

  • Protons are positively charged subatomic protons that exist within the nucleus of the atom.
  • They weigh 1 amu.
  • They are attracted to other subatomic particles (neutrons) by the strong nuclear force).

Neutrons

  • Particles that have a neutral charge that exist within the nucleus of the atom.
  • They weigh 1 amu.

Electrons

  • Negatively charged subatomic particles that exist outside the nucleus of the atom in the electron cloud
  • Because of their extremely light weight in comparison to protons and neutrons, electrons are said to be relatively mass-less.

Scientific Contributions to the Current Atomic Model

Models of the Atom

There are three central players to the development of the atom. They are J. J. Thomson, Ernest Rutherford, and Niels Bohr. These men were ruthless killers in their own respective Hunger Games, so an in depth history of each of them will provide insight on how best to beat District 1.

Evolution of the Atomic Model

JJ Thomson's Experiment

Attached a battery to the cathode tube and saw a beam form. He concluded that the beam must contain subatomic particles because the cathode tube was a vacuum. He put a positive magnet next to the beam and it bent towards the magnet. Put a negative magnet next to the beam and it bent away from the magnet.

Thomson had discovered the electron! The beam had to have been negatively charged because negative charges are attracted to positive magnets and repelled by negative magnets. Therefore, the beam contained negatively charged subatomic particles that he called electrons.

Thomson did NOT discover the location of these electrons, rather he merely discovered the existence of them.

Ernest Rutherford Hypothesis

Ernest Rutherford was a student of J. J. Thomson and he provided additional evidence to further develop the view of the atom. He provided additional evidence using the gold foil experiment.

Rutherford took positively charged alpha particles and shot them at a piece of gold foil that was as thick as tissue paper. Most particles went straight through the foil. Small amount of the particles were deflected, but still went through. An even smaller amount were fired back at the original source.

Most of the alpha particles went straight through because the atom is mostly empty space. Some alpha particles showed slight deflections because they came close to the negatively charged electrons. The few alpha particles that bounced back were coming into contact with the very small, but very dense positively charged nucleus.

Niels Bohr's Discovery

Scientists knew that if you shot electricity through a tube of hydrogen gas, a bright color would be produced. If you looked through a special lens, you knew that only a few colors were being emitted.

Bohr knew that shooting electricity through the hydrogen excited the electrons. A color was produced when electrons returned to original state. There was a problem through: if electrons were free to roam, then we should get all sorts of colors, but we only get those four colors.

He did not solve this using an experiment. He solved it using only math. Electrons are not free to roam in the electron cloud, electrons are restricted to orbits or energy levels.

Turning Atoms into Ions

The Bohr model of the atom confined electrons to certain orbits. The first orbit holds 2 electrons Every other orbit after the first orbit holds 8 electrons. The electrons on the outermost orbit are known as valence electrons.

The Octet Rule states that atoms like to have a full outer valence shell. They will gain or lose electrons in order to have an outer orbit with 8 electrons. They will gain or lose based on what is easiest.

All elements in the same group gain/lose the same number of electrons because they all have the same number of valence electrons. Atoms are neutral, but when they gain/lose electrons they take on a charge and become an ion. By gaining electrons, an atom becomes a anion (negatively charged ion) due to the fact that it now has more electrons than protons. By losing electrons, an atom becomes a cation (positively charged ion) due to the fact that it has more protons than electrons.

Practice!

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Harness the Power of Your Atoms

At the cornucopia you obtained a beta gun. Recall that beta particles are electrons. As you run from the cornucopia you fire the gun at the District 1 tributes. To determine if the shots hit the tributes, complete the following assessment: SEE ASTOR FOR DISTRICT 1 ASSESSMENT

Other Useful Resources