Chemical Bonding Test

Personally, I did not think the test was that hard. I studied long and hard to make sure my first grade for the quarter would start strong. There was a wide range of questions covering every topic we covered and even a little more. Many of the questions were taken directly of the schoology quizzes so I was able to spend less time on those and focus on the harder questions.

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It scared me when I first looked at my grade after the test because she had put the wrong grades in and mine was much lower than I thought it would be. Thankfully, she fixed the grades and I did fairly well. Most of the questions I missed were because of a stupid mistake. For example, one question asked what was the shape of Y and I looked at the shape of X. Overall, I didn't think the test was too terribly hard.

Some websites I used to study are:
Resonance
Chemical Bonds and the Shape of Molecules

Chemical Bonding Activity

Today we met in the library and working on chemical bonding problems with three other people. We sat on these little bean bags that we a little uncomfortable at a little table but that was the only bad part. This activity really helped me to understand the many different parts of the unit. By talking it through with partners and drawing it out on the table, I was really able to visualize the concepts that we learned in class. 

Types of Bonds, Bond energy, and Lewis Structure

Covalent vs Ionic Bonds
Covalent Bonds

• result of the sharing of electons by two nonmetals
• both atoms involved in the bond share electrons to fill their particular octet

Ionic Bonds

• involves the giving and reciving of electrons between a cation and an anion
• oppositely charged ions then attract to each other forming a bond

Octet Rule

• Atoms cannot have more than 8 electrons 
• A full 8 electron shell is considered stable
• Some atoms don't need 8 electrons

Exceptions to the rule:

• hydrogen and helium only requires 2 electrons
• boron only requires 6 electrons to be stable, but it will form 4 bonds when necessary
• beryllium will have fewer than 8 as well, it likes 4 electrons in its valence
• elements in period 3 and beyond can have expanded octets because the d sublevel becomes available (ex. sulfur, phosphorus, xenon, krypton)

Lewis Strucutre for Atoms

• figure out how many valence electrons are needed for the atom
• write the atom's symbol in the center
• place electrons singularly on each side before doubling up the electrons until all valence electrons are placed
• EX: Nitrogen has 5 valence electrons which are placed in the Lewis structure below
  

Bond Length and Energy

• Single bonds: longest and weakest bonds
• Double bonds: shorter and stronger than single bonds
• Triple bonds: shortest and strongest bonds

• read from right to left
• the lowest point on the graph is high energy and where the bond forms
• 0 energy is when the two atoms are isolated from each other
• energy being absorbed is the same amount of energy being released

Periodic Table Trends

Trends in Atomic Size

• As you move down a group, the atoms tend to get larger. (electrons are being added to larger orbitals and inner electrons tend to shield the nucleus so the outermost electrons tend to fell less pull or attraction from the nucleus)
•  And as you move across a period from left to right, the atomic size decreases. (adding more protons without much increase in shielding)

Trends in Ionization Energy

• Ionization energy- the energy needed to remove an electron from a gaseous atom
• removing an electron results in the formation of a cation
• The energy required for removal of the first electron is known as the first ionization energy. The energy required for removal of the second electron is known as the second ionization energy.

Trends in Electron Affinity

• Electron Affinity- the ease with which an electron many added to an atom, forming an anion
• Increases as you move up and to the right.
• 
  

Trends in Electronegativy

• Electronegativity of an element is defined to be the tendency of an atom to draw electrons toward itself when chemically combined with another element.
• Noble gases are not included

Difference between the two