Atomic Number Increases

In this experiment, you will have a chance to test the hypothesis that Ernest Rutherford used when determining the size of the nucleus. In his "gold foil experiment," Rutherford shot alpha particles at gold atoms. Once he realized that the alpha particles were hitting a concentrated positive mass, he developed the nuclear model of the atom. Next, he set out to determine the relative size of the nucleus compared to the rest of the atom. He reasoned that the smaller the nucleus, the less likely it was to be hit by an alpha particle. This led to a simple comparative ratio:

The students created a macroscopic, three-dimensional (3D) model of several properties of the periodic table. They explained in their own words the following terms: atomic radii, ionic radii, first ionization energy, and electronegativity. Lastly, they identified, described, and explained the patterns observed in the 3D periodic tables for the following element properties: atomic radii, ionic radii, first ionization energy, and electronegativity.

As more electrons are added the distance will increase which cause atomic radius to change.

To understand how this electricity works we must start with the basics. The atom is the smallest unit of matter, consisting of protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. Electric charges that are the same repel each other and charges that are different attract each other. Electric charges can exist alone, unlike magnetic poles.

The two assignments that I have included in this section is my Average Atomic Mass worksheet and Capstone review packet. For the Average Atomic Mass worksheet, I had to find the average atomic mass for each element. For the Capstone review packet, I had to answer different questions on different questions.

For each element, we believe that its mass and atomic number have a positive linear relationship. We can expect that as the atomic mass increases, the mass of the gas will increase as well.

Atoms are made of three parts, protons, neutrons, and electrons. Protons are pieces of matter that is positively charged (+1). Electrons are really small, smaller than protons, piece of matter with a negative charge(-1). Neutrons are pieces of matter around the same size as protons with no charge(0). Atoms are usually surrounded by electrons. When the electron and protons are at the same amount the net charge is zero. When the number of electrons and protons are not equal it causes the atoms to be ionized. These atoms are called ions. More electrons over protons are negatively charged. More protons over electrons are positive charged. The total charge would be the sum of the positive protons and negative electrons. The number of protons defines

1. What are chemical symbols? Give some examples. 2. Define atom.

Now that we know how atoms lose electrons, how do atoms gain electrons? When atoms gain electrons it usually has more than 4 valence electrons. This transforms a atom from a neutral state to a negative state therfore turning the atom

The atomic radius and the atomic number function as a trend. In each period of the periodic table, as the atomic number increases, the atomic radius decreases. For example, the atomic number of Lithium is 3 and its atomic radius is 152 pm. The atomic number of Beryllium is 4 and its atomic radius is 111. There are 6 individual curves in the graph. The trend shows that as you move throughout the periodic table, the previous element’s radius gets smaller compared to the first element of the next level. For example; Neon’s atomic number is 10 and its atomic radius is 65, Sodium’s atomic number is 11 and its atomic radius is 186.

The Strong Nuclear Force (also referred to as the strong force) is one of the four basic forces in nature (the others being gravity, the electromagnetic force, and the weak nuclear force). As its name implies, it is the strongest of the four. However, it also has the shortest range, meaning that particles must be extremely close before its effects are felt. Its main job is to hold together the subatomic particles of the nucleus (protons, which carry a positive charge, and neutrons, which carry no charge. These particles are collectively called nucleons). The protons must feel a repulsive force from the other neighboring protons. This is where the strong nuclear force comes in. The strong nuclear force is created between nucleons by the exchange of particles called mesons. This exchange can be likened to constantly hitting a ping-pong ball or a tennis ball back and forth between two people. As long as this meson exchange can happen, the strong force is able to hold the participating nucleons together. The nucleons must be extremely close together in order for this exchange to happen. The distance required is about the diameter of a proton or a neutron. If a proton or neutron can get closer than this distance to another nucleon, the exchange of mesons can occur, and the particles will stick to each other. If they can't get that close, the strong force is too weak to make them stick together, and other competing forces (usually the electromagnetic force) can influence the particles to move apart. This is represented in the following graphic. The dotted line surrounding the nucleon being approached represents any electrostatic repulsion that might be present due to the charges of the nucleons/particles that are involved. A particle must be able to

“What is the world made of?” That question has puzzled scientists and philosophers for centuries. The atomic theory was first proposed in ancient Greece around 400 BC and has continued to evolve through the centuries to finally evolve into the current theory we have today. We now know that the subatomic particles that make up the atom are no longer the fundamental particles of the universe because even they are made of smaller particles called “quarks.” The continuous study of atoms will allow us to truly understand the universe and harness it’s knowledge to further science and technology for the good of society.

1. Electric charges attract or repel one another with a force inversely proportional to the square of the distance between them: unlike charges attract, like ones repel.

All the forces involved in interactions between atoms can be traced to the electromagnetic force acting on the electrically charged protons and electrons inside the atoms. This includes the forces we experience in "pushing" or "pulling" ordinary material objects, which come from the intermolecular forces between the individual molecules in our bodies and those in the objects. It also includes all forms of chemical phenomena, which arise from interactions between electron orbitals.

The outer shell of electrons that orbit the nucleus of an atom is called the valance shell. This is what makes a copper atom conduct. For a copper atom the number of electrons is one. When a charge of electricity is placed in the end of a wire the electrons move into the wire. Since there is only one electron in the valance shell of a copper atom it can be easily dislodged with a small amount of energy causing it to jump to the next atom. This will then cause the valance electron of that atom to jump to the next atom and so forth. This movement happens very fast making it possible for a large number of electrons to move through the wire. An example of a conductive atom is shown figure 1.