Advanced Chemistry- The Periodic Table
Hund's Rule
- electrons occupy equal energy orbitals so as to maximize the number of unpaired e-s
Calculate the wavelength of a photon having energy of 1.257 X 10-24 joules. (Planck's constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)
0.158 m
A ray in the emission spectrum has a wavelength of 3.10 x 1014 meters. Given that the speed of light is 2.998 x 108 m/s, what is the frequency of the ray?
0.967 x 10-5 HZ
Family one Valence Electrons
1
Families 3-12 Valence Electrons
1 or 2
s sublevel
1 orbital
18 Vertical Columns
18 Families
What is the electron configuration of an element with atomic number 15?
1s2 2s2 2p6 3s2 3p3
Family 2 Valence Electrons
2
s block
2 electrons, 1 orbital
Family 13 Valence Electrons
3
p sublevel
3 orbitals
Family 14 Valence Electrons
4
Family 15 Valence Electrons
5
d sublevel
5 orbitals
Family 16 Valence Electrons
6
How many valence electrons does oxygen have?
6
Family 17 Valence Electrons
7
f sublevel
7 orbitals
7 Horizontal Rows
7 periods
Family 18 Valence Electrons
8 except Helium (He) has only 2
Calculate the change in energy of an atom that emits a photon of wavelength 2.21 meters. (Planck's constant is 6.626 x 10-34 joule seconds, the speed of light is 2.998 x 108 m/s)
8.9886 x10-26 joules
Covalent Bond
A chemical bond that involves sharing a pair of electrons between atoms in a molecule
Insulator
A material that does not allow heat or electrons to move through it easily.
Ductile
A term used to describe a material that can be pulled out into a long wire.
Aufbau principle.
An electron occupies the lowest-energy orbital that can receive it
Go through all the elements in group 6A, moving from top to bottom. What do you notice about the pattern of change in the electron configuration as you go from top to bottom?
As I go down group 6A, I find that all elements in this group have six electrons in their outermost energy level. The energy level also increases by one for each element as I move down the group. For example, the outermost energy level for oxygen is two; for sulfur, three; for selenium, four; and so on.
metals
Clean metals have a shiny, metallic luster. Metals also conduct electricity and heat. For example, electricity travels easily through copper wire because electrons pass readily from one metal atom to another. Except for mercury, the silver liquid found in many thermometers, all metals are solid at room temperature. Solid metals are typically hard, although some, such as the alkali metals, can be cut with a knife. Most metals are malleable, meaning that they can be hammered into shape or rolled into sheets. Metals are also ductile. They can be stretched into wire. The chemical properties of metals vary widely. Metals such as platinum or gold are fairly nonreactive and don't rust or tarnish easily. Other metals react quickly with oxygen or even the moisture in the air.
exeptional electon configuration ex.
Copper's configuration differs from what you'd expect because completely full d orbitals make the electron configuration more stable. So, one of copper's 4s electrons moves into the 3d sublevel since the atom seeks stability.
Dmitri Mendelev
Created the periodic table
Metals
Elements that are good conductors of electric current and heat.
Metalloids
Elements that have properties of both metals and nonmetals.
Ionic Bond
Formed when one or more electrons are transferred from one atom to another
alkali metals
Group 1, 1 electron in outer level, very reactive, soft, silver, shiny, low density; Lithium, Sodium, Potassium, Rubidium, Cesium, Francium
Halogens
Group 17. Contains nonmetals, 7 valence electrons in it's outermost energy level. Very reactive
Noble Gases
Group 18; do not bond
transition metals
Groups 3-12, 1-2 electrons in the outer energy level, less reactive than alsali-earth metals, shiny, good conductor of thermal energy and electrical current, high density
d block
Groups 3-12, transition metals
the fourth period, starting with the element in the 1A group. Go from left to right. What do you notice about the pattern of change in the electron configuration as you go from left to right?
In the electron configuration of potassium, I observe that after the 3p orbital is filled, the next electron enters the 4s orbital instead of the 3d orbital because 3d is at a higher energy than 4s. This pattern shows that orbitals fill up according to the Aufbau principle. As I move on right, the number of electrons increases by one for each element until vanadium is reached. The electron configuration of chromium shows all half-filled orbitals in the 4s and 3d energy levels. Again, as I move right, an exception occurs at copper. Copper's electron configuration shows completely filled 4s and 3d orbitals. This is an exception to the Aufbau principle to attain more stable electron configurations, whenever possible. Half-filled electron configurations are more stable than other configurations and completely filled electron configurations are the most stable.
When an electron of an atom returns from an excited state to the ground state, it emits energy in the form of a photon. How does the change in energy level compare to the energy of the emitted photon?
It is equal to the energy of the photon.
Only two elements are this state of matter at room temperature ...
Liquid
8A elements
Located on the right edge of the table, the elements in group 8A are known as the noble gases. These elements are chemically stable and nonreactive. They tend not to gain, lose, or share electrons easily because of their stable electron configurations, which you'll learn more about later. In the past, these elements were often called the "inert gases" since they are almost completely nonreactive.
Non-metals
Low conductivity, not ductile, not malleable, brittle, dull, gas at room temp
Metalloids or Semimetals
Metalloids exhibit properties between those of metals and nonmetals, corresponding to their location between the metals and nonmetals in the periodic table. Metalloids tend to behave as nonmetals in many ways, but they show some electrical conductivity, a characteristic of metals. Rather than being electrical conductors, several of the metalloids—silicon and germanium in particular—are semiconductors. Semiconductors don't transfer electrical charges as well as conductors, but they do it better than insulators, which do not conduct any significant current. Silicon is the primary element used in making semiconductor wafers for integrated circuits, computer chips, and solar cells. Fortunately, this important element is abundant on Earth. Silicon dioxide, commonly known as silica, is the most common mineral in Earth's crust. Sand is mostly composed of silica.
Periodic Table Arrangement
Most elements are metals, a few are metalloids, and a little over a dozen are nonmetals. All the elements in the left and center of the table, other than hydrogen, are metals. About a dozen elements in the upper right corner, plus hydrogen, are nonmetals. A small handful in between the metals and nonmetals are metalloids.
Consider Group 5A elements: nitrogen, phosphorus, and arsenic. These elements show an increase in their atomic numbers. Which element has the highest ionization energy?
Nitrogen
Nonmetals
Nonmetal elements are not malleable or ductile, they do not possess metallic luster, and most are poor conductors of heat and electricity. Nonmetals vary widely in their properties and reactivity. Some nonmetals, such as helium, exist as a gas composed of single atoms. Other nonmetals, such as fluorine, exist as gases composed of diatomic molecules in which two atoms are bonded together. Helium is extremely nonreactive, while elemental fluorine reacts with many elements, including other fluorine molecules. The states of nonmetal elements vary. For example, elemental bromine is a liquid at room temperature while other nonmetals, such as sulfur, are soft solids. Sulfur crumbles when hammered, but diamond, one form of solid carbon, is the hardest natural substance known.
7A elements
On the right side of the periodic table, elements in group 7A are collectively known as halogens. These highly reactive elements are often found combined with other elements as salts. In fact, the term halogen means "salt former." For example, chlorine combines with sodium to form the compound sodium chloride, or common table salt.
When creating an orbital diagram
Place the arrows that represent electrons in the orbitals one at a time. Always begin with the 1s orbital because it has the lowest energy. No orbital can have more than two electrons, and the two electrons have opposite spin (shown by up or down arrows). If a level has more than one orbital of the same type, first distribute one electron into each orbital and then add the second electron to each. Once all orbitals are filled in an energy sublevel, move to the next highest sublevel.
Families Have ...
Properties and Valence Electron Numbers in Common
Sublevel
Regions of space that electrons occupy make up a principal energy level.
Azimuthal Quantum Number
Second quantum number, designated l. Tells us the shapes of the electron orbitals; The s, p, d, and f orbitals have different shapes, and each has a different value for l. Depending upon the value of l, we can determine whether it's an s, p, d, or f orbital. Integral values for l range from 0 to n − 1 for each value of n.
Rare Earth Elements
Seventeen chemical elements that commonly occur together but are difficult to separate. They are commonly used to make high tech electronics and weapons systems.
Properties of Metals
Shiny luster, high malleability, ductility, electrical and thermal conductivity.
In a reaction, chlorine accepts an electron to form Cl-. Which statement is true about the atomic size of the chlorine ion?
The atomic size of the chlorine ion is larger than the size of the chlorine atom.
Go through the elements in the second period, going from left to right. What do you notice about the pattern of change in the electron configuration as you go from left to right?
The first element, lithium, has the electron configuration 1s2 2s1. As I move to the next element, beryllium, one more electron is added to the 2s orbital, resulting in the electron configuration 1s2 2s2. As I move farther right, the number of electrons increases by one for each element. I can see how the Aufbau principle, the Pauli exclusion principle, and Hund's rule are followed while the electrons are filling up the orbitals.
2A elements
The group 2A elements are also metals that form alkaline-oxygen compounds. These elements don't dissolve in water as readily as the group 1A elements, however. As a result, they're often found in earthy soil deposits and are called the alkaline earth metals.
Spin Quantum Number
The spin quantum number is represented by ms. It describes the rotation of an electron in its orbital. You know that two electrons in the same orbital have an opposite spin. So, the spin quantum number has only two values, -1/2 or +1/2. If an electron shows an up, or clockwise, spin, ms is +1/2. If it shows a down, or counterclockwise, spin, then ms is -1/2. The spin quantum number distinguishes between the two electrons in the same orbital and indicates their opposite spins.
Which of the following statements is correct with respect to electron spin?
The two electrons in one orbital attract each other if they have the same spin.
Element Groups
There are a lot of ways to "slice up" the periodic table. Here, it's divided into three major sections. Elements in groups 1A through 8A are known as the main group elements. Elements in the B groups at the center of the periodic table are known as the transition metals. The final group, inner transition metals (lanthanides and actinides), fit into the main body of the periodic table, but they're usually pulled out to conserve space.
Electrons that are the farthest from the nucleus: help atoms bond with other atoms.
Valence Electrons
How is an emission spectrum of an element generated?
When an electron in an atom returns from an excited state to a lower energy state.
Metallic Bond
a bond formed by the attraction between positively charged metal ions and the electrons around them
Conductor
a material that conducts heat well; a material through which charges can easily flow
Which of these elements is unlikely to have a reaction with any element or compound?
argon (Ar) (the noble gases are least reactive)
Periodic Table in order by ...
atomic number (number of protons)
How is the modern periodic table arranged?
by atomic number, with chemical families or groups in columns and periods in rows
Which of these elements is an alkaline earth metal?
calcium (Ca)
Malleable
capable of being shaped
Which of these elements is a transition metal?
chromium (Cr)
Hund's Rule
electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible
p block
groups 13-18
Looking at the periodic table, which of these elements has the smallest atomic radius?
hydrogen
f block
inner transition metals
What happens when an electron moves from a high energy level to a lower one?
it emits light
Principle Energy Level
main energy level or distance of an electron from the nucleus; (n); correspond to the rows 1-7 on the Periodic Table
Pauli Exclusion Principle
maximum of two electrons may occupy an atomic orbital, but only if they have opposite spins
Alkaline Earth Metals
metallic elements in group 2 of the periodic table which are harder than the alkali metals and are also less reactive
What is the principal quantum number value for the highest energy electron in carbon (atomic number 6)?
n = 2
What does the Pauli exclusion principle state?
no two electrons in the same atom can have the same set of four quantum numbers; Two electrons occupy the same orbital only if they have opposite spins.
What is the name of the collection of elements on the right side of the periodic table with electrons sequentially filling orbitals in their valence?
p-block elements
A(n) ... is a horizontal row in the periodic table.
period
Which of the following elements is an alkali metal?
potassium (K)
Which electromagnetic wave has the longest wavelength?
radio waves
Which of these elements reacts rapidly when dropped in water?
rubidium (Rb)
Which of the following elements is a metalloid?
silicon (Si)
Which of these elements has four valence electrons?
silicon (Si)
Most of the Periodic Table is this state of matter at room temperature ...
solid
quantum numbers
specify the properties of atomic orbitals and the properties of electrons in orbitals; Quantum numbers describe the state of an electron, that is, its location, energy, and spin within an atom. There are four quantum numbers: the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number.
Pauli exclusion principle.
states that a maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins
Aufbau Principle
states that each electron occupies the lowest energy orbital available
Magnetic Quantum Number
symbolized by m, indicates the orientation of an orbital around the nucleus; It describes the orientation in space of the orbital in which the electron lies with respect to the other atomic orbitals. The integral values of ml range from -l to +l.
principal quantum number
symbolized by n, indicates the main energy level occupied by the electron; Depending upon the size and energy level of the orbitals, n has integer values such as 1, 2, 3, and so on. It's an indication of how far away an electron is from the nucleus. As the n value increases, the distance of the electron from the nucleus also increases. Higher n values also mean the electrons have higher energy values.
electron configuration
the arrangement of electrons in an atom
electron configuration
the arrangement of electrons in the energy levels, sublevels and orbitals of atoms
electron configuration
the arrangement of electrons in the orbitals of an atom
noble gases
the elements in Group 8A of the periodic table
alkali metals
the elements in group 1A at the left of the periodic table, excluding hydrogen, are known as the alkali metals. These highly reactive elements tend to form oxygen-containing compounds that dissolve in water to produce solutions that are strongly alkaline, or basic, on the pH scale.
The wavelength of a given region of the electromagnetic spectrum ranges from 1 x 10-11 - 1 x 10-8 meters. Which waves are found in this region?
x-rays
