Unit 4: The Quantum Model of the Atom and Periodic Properties Flashcards
The Heisenburg Uncertainty Principle
You cannot determine both the speed and the location of a particular electron at the same time.
DeBroglie
Using Bohr’s model of the atom, he investigated the photoelectric effect and determined that electrons had wave-like behavior along with particle behavior, and this wave-like behavior gave them a certain frequency.
Photoelectric Effect
the energy given off when light strikes metal
Erwin Schrodinger
developed an equation that treated electrons in atoms as waves and this, along with Heisenburg’s research, laid the foundation to the Quantum Theory
Max Planck
suggested that hot objects emit energy in small, specific amounts called Quanta
Albert Einstein
capitalized on Planck’s suggestion with the idea that electromagnetic radiation had wavelike properties, that particles will “stream” and that each particle of light carries a certain quantum of energy
Quantum Theory
gives us a mathematical description of the wave properties of electrons and other very small particles
Principle Quantum Number
indicates the size of the atom and is symbolized using the letter “n”. “n” can be determined by locating the row the element is on as placed on the periodic table
Azimuthal/Angular Momentum Quantum Number
indicates the sub levels of the main energy levels and is symbolized by the letter “l”. Also symbolized by the letters “s”, “p”, “d”, “f”, “g”, etc.
Magnetic Quantum Number
indicates the orientation of the electrons on an “x”, “y”, “z” axis and is symbolized by the letter “m”.
Spin Quantum Number
indicates the direction in which the electrons are traveling, +1/2 or -1/2 or by using alternating arrows.
Hund’s Rule
electrons will remain unpaired as long as possible, because they have the same charge, and that like-charge will cause repulsion and excess energy. When filling sub levels, electrons will alternate spaces to put as much distance between each other before pairing
Electron Configuration Notation (ECN)
a shorthand method used to write the electron configuration of elements
Shorthand ECN
uses noble gas to represent sub levels that are perfectly filled
Valence
electrons found in the last main level of an atom
Ionic Bonds
will form between metals (cations) and nonmetals (anions) and produce compounds with high melting points that are also hard and brittle. This forms by a transfer of valence electrons.
Covalent Bonds
form when valence electrons are shared between two or more atoms, usually nonmetals
Dmitri Mendeleev
published the 1st periodic table in 1869 based on increasing atomic weight. He left blanks for elements he knew were still undiscovered. He also did not have an element representative of the Noble gases, because they had not been discovered yet (they were discovered in the late 1800s, early 1900s)
Henry Mosely
used x-rays to confirm Mendeleev’s periodic chart which led to the Periodic Law
Periodic Law
states that the physical and chemical properties of the elements are periodic functions of their atomic numbers
How many groups does the periodic table have?
18
How many series (sometimes called periods) does the periodic table have?
7
Group I of the periodic table; all of these have one valence electron, explode when placed in water; form VERY strong bases, such as sodium hydroxide
Alkali Metals
Chemical Bond
a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together
Group II of the periodic table; all of these elements have 2 valence electrons. These elements are found in many compounds in nature such as limestone and chlorophyll
Alkaline Earth Metals
Groups 3-12 of the periodic table; these elements vary in their number of valence electrons. These elements are known for their brightly colored compounds.
Transition Metals
Group 17 of the periodic table; these elements have 7 valence electrons. They are the most active nonmetals. They can form very strong acids, such as HCI, hydrochloric acid-stomach acid.
The Halogens
Group 18 of the periodic table; all BUT helium have 8 valence electrons. They are all gases, all perfect, all non-reactive, all inert. Helium has 2 valence electrons.
The Noble Gases
Atomic Radius
one-half the distance between like nuclei that are bonded together. It increases as you go down a group, decreases as you move from left to right on the periodic table. Metallic characteristics decrease as you go left to right, decreases as you go from top to bottom. If energy is high, it is small.
Ionization Energy
the energy required to remove valence electrons from an atom. It increases from left to right on the periodic table, decreases from top to bottom in a group. It is higher when the radius is small.
Electronegativity
the measure of the ability of an atom to attract shared electrons. It increases from left to right on the periodic table, decreases from top to bottom in a group. It has the same trend as ionization energy. It is low in metals, but high in nonmetals. It is higher when the radius is small.
Electron Affinity
the attraction an atom has for shared electrons. This increases from left to right, decreases from top to bottom.
Large Negative Ions
indicate that the negative ion formed is very stable
Small Negative Ions
indicate that a less stable ion is formed
What does a “0” mean in terms of electron affinity?
If you were to add another electron, it would have to go into the next main energy level and would absorb energy to do this, not release it.
Ion
charged particles
Cation
Positive ions, usually metals. These elements donate valence electrons to another element so that they and the element they are donation to can form a stable compound. The atomic radius is smaller than their parent atom.
Anion
Negative ions, usually nonmetals. These elements receive valence electrons from another element so that they and the element donating the electrons can form a stable compound. The atomic radius is larger than the parent atom.
