District 2 - Periodic Table and Trends
Welcome to your training for how to take down District 2 when you are in the arena. Where would these other Districts, and the Capital for that matter, be without the Periodic Table? District 2 knows this advantage and will likely take advantage of it. They have a deep understanding of elements and how they work, so you are going to need to become an expert if you are going to take this District down once the Games begin. They are advised by past champion Dmitri Mendeleev. It is rumored that he has gone crazy and this may be useful information once you are inside the arena.
Past District 2 Champions
Your Training
Training Resources
The Periodic Table of Elements
Please take out your District 2 guided notes and watch the lecture below.
An element is a substance that cannot be separated/broken down into simpler substances by chemical means. An element consists of only one type of atom
On the Periodic Table, we are told the following about every element:
There are groups and periods on the Periodic Table. A group is a vertical column on the Periodic Table. A period is a horizontal row on the Periodic Table. Elements in the same group have similar properties. Therefore, each group on the Periodic Table has special names and properties. These properties are due to the fact that elements in the same group have the same number of valence electrons. Alkali Metals:
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Metals, Non-metals, and Semimetals
Elements on the Periodic Table are classified as metals, non-metals, or semimetals. We can identify them based on their location on the Periodic Table.
Metals are shinny, solids at room temperature, and they are malleable. If something is malleable, then this means that is is able to be hammered or pressed permanently out of shape without breaking or cracking. They are also good conductors of heat and electricity. This means that they are able to draw a current/heat through the material. Non-metals are dull, gases at room temperature, and they are not malleable. Additionally, they are poor conductors of heat and electricity, so we call them insulators. If something is an insulators then this means that they resist the flow of heat or electricity through the material. The final group of materials semimetals. This is a select group of elements that have characteristics of both metals and non-metals. Semimetals look metallic, but are brittle. They are neither good nor bad conductors or insulators, so we call them semi-conductor. It is rather easy to locate metals, non-metals, and semimetals on the Periodic Table. The “staircase” separates metals from non-metals on the Periodic Table Elements to the left of the staircase are metals Elements to the right of the staircase are non-metals Elements that touch the staircase (except aluminum) are semimetals. There is one exception to the rule and that is hydrogen. Hydrogen is located to the left of the staircase, but hydrogen is a non-metal. |
Periodic Trends
Please take out your District 2 guided notes and watch the lecture below.
Ionization Energy:
The negatively charged electrons are attracted towards the positively charged nucleus. This attraction plays a major role in the periodic trends that are observed for elements. Nuclear attraction is responsible for all the trends that are observed for element.
Ionization energy is the energy that is required to remove an electron from an atom. This is the energy that is required to turn our neutral atom into an ion. This is different depending on the element. As you move down a group the ionization energy decreases. As you move across a period on the Periodic Table, the ionization energy increases. As you go down a group more electron orbits are added. Ionization energy decreases as you go down a group because it requires much less energy to remove a valence electron due to the shielding. As you move across a period you add more protons and electrons within the same electron orbit. The larger amount of protons in the nucleus and the larger amount of electrons show an increased attraction. results in it being much harder to pull away electrons as you add more protons within a period and a higher ionization energy as you go across a period. |
Electronegativity:
We can categorize atoms based on their ability to attract electron Electronegativity is the measure of the ability of an atom to attract electrons. We can also call this the strength of the atom. The priniciples of nuclear attraction that are observed in ionization energy are also observed in this periodic trend.
As you go down a group, the electronegativity of an element decreases. As you go across a period, the electronegativity of an element increases. As you go down a group more electron orbits are added. Electronegativity decreases because there is a decreased ability of the positively charged nucleus to attract valence electrons as a result of this larger distance and a decrease in electronegativity as you go down a group. As you move across a period you add more protons and electrons within the same electron orbit. The larger amount of protons in the nucleus and the larger amount of electrons show an increased attraction. This results in a much larger ability for the positively charged nucleus to attract valence electrons within a period and an increase in electronegativity as you go across a period. |
Atomic Radius:
The atomic radius is the distance from the center of the nucleus to the outermost edge of the electron cloud for an atom.
Atomic radius increases as you go down a group on the Periodic Table. Atomic radius decreases as you go across a period on the Periodic Table. As you add more electron shells to an element, the element becomes “bulkier” due to the increased amount of electron orbits. This means that as you go down a group, more orbits are added, so the atomic radius becomes bigger. As you move across a period, more protons are added to the nucleus. Also, more electrons are added within the same electron orbit. This means there is a larger positive and negative charge, which results in a higher attraction and the atomic radius to decrease. |
Practice Problems
Try the following practice problems:
Answer Key: |
The Mysterious Elements
The District 2 tributes have a large amount of elements at their disposal, but you were able to obtain a vile of mercury at the cornucopia. You dip your arrow into the vile and aim it at the leg of the tributes (mercury poisoning is sure to get you sponsors). To see if this is successful, complete the following assessment
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Extra Resources
Still confused? Check out these awesome resources!:
- Khan Academy Periodic Table and Trends
- Brightstorm Periodic Table and Trends
- Brainpop Videos (ask Mr. Lance for login information)