Chemistry Unit 6
Green on periodic table
Metalloids (border the heavy stair step line that separates the metals from the nonmetals)
Yellow on table
Metals
There is a heavy _________ ______ that separates the metals from the nonmetals.
stair-step line
Outermost electrons can get _______ bc less attraction, electron is physically removed
stolen
Electronegativity
(can be used to predict the type of bond that will form during a reaction.) the ability of an atom of an element to attract electrons when the atom is in a compound.
Why does atomic size generally increase as you move down a group of the periodic table and decrease as you move from left to right across a period?
* As you move down a group, an energy level is added, increasing the size of the atom * As you move from left to right across a period, the nuclear charge becomes a stronger positive, pulling the electrons close, decreasing the size of the atom.
Why is the first ionization energy of a nonmetal much higher than that of an alkali metal?
* Nonmetals have more filled shells, making it harder to remove electrons. * Nonmetals have smaller atoms, while metals have larger atoms and therefore less attraction of the electrons to the nucleus. The nuclear charge increases from left to right across a period and the shielding effect stays the same. So it is more difficult to remove an electron from a nonmetal than an alkali metal
Trends across a period Atomic size: Ionization energy: Electronegativity: Nuclear charge: Shielding: Size of cations: (followed by) Size of anions:
- Atomic size decreases - Ionization energy increases - Electronegativity increases - Nuclear charge increases - Shielding is constant - Sizes of cations decreases - sizes of anions decreases
Trends down a group- Atomic size: Ionic size: Ionization energy: Electronegativity Nuclear charge: Shielding:
- Atomic size increases - Ionic size increases - Ionization energy decreases - Electronegativity decreases - Nuclear Charge increases - Shielding increases
The least electronegative element in the table is _______, with an electronegativity of 0.7.
- Cesium (It has the least tendency to attract electrons. When it reacts, it tends to lose electrons and form cations.)
However, based on its _______ ________ iodine belongs in a group with bromine and chlorine
- Chemical properties
The increase in positive charge draws electrons _______ to the nucleus. But as each energy level is added, the protons have ______ of a pull on the electrons in the highest energy level
- Closer, Lesser
From left to right across a period, two trends are visible—a gradual _________ in the size of the positive ions (cations), followed by a gradual ________ in the size of the negative ions (anions).
- Decrease - Decrease
First ionization energy tends to ________ from top to bottom within a group and ________ from left to right across a period.
- Decrease - Increase
There is also a vertical column with the numbers 2, 8, and 3, which indicate the number of _____________ in each occupied energy level of an aluminum atom
- Electrons
How are elements arranged in Mendeleev's table and very early chemists'?
- Elements in a periodic table are arranged into groups based on a set of repeating properties. - Mendeleev arranged elements with similar properties in the same row.
The most electronegative element is ________, with a value of 4.0.
- Fluorine (Because fluorine has such a strong tendency to attract electrons, when it is bonded to any other element it either attracts the shared electrons or forms an anion.)
The elements between zinc and arsenic were g_______ and g________, which were discovered in 1875 and 1886, respectively
- Gallium - Germanium
The shielding effect is ________ than the effect of the increase in nuclear charge, so the atomic size ________
- Greater - increases
Halogen comes from the combination of the Greek word ____, meaning "salt" and the Latin word _______, meaning "to be born"
- Hals - Genesis
There are more elements in _______ numbered periods because there are more ______ in higher energy levels
- Higher - Orbitals
The atomic size ________ as the atomic number increases within a group.
- Increases
The nuclear charge ________ across the period, but the shielding effect remains _________.
- Increases - Constant (As a result, there is an increase in the attraction of the nucleus for an electron. Thus, it takes more energy to remove an electron from an atom.)
In general, the first ionization energy of representative elements _________ from left to right across a period. This trend can be explained by
- Increases - the nuclear charge and the shielding effect.
These nonmetals are sometimes called the _____ gases because...
- Inert - they rarely take part in a reaction
____ _______ is required to remove an electron from this energy level, and the first ionization energy is lower.
- Less energy
During reactions between metals and nonmetals, metal atoms tend to ____ electrons and nonmetal atoms tend to ____ electrons
- Lose - Gain
Metals that are representative elements tend to ____ all their outermost electrons during ionization. (Therefore...)
- Lose - the ion has one fewer occupied energy level.
Pure silicon is a _____ conductor of electric current. However if a small amount of ______ is mixed, the mixture is a ______ conductor of electric current
- Poor - Boron - Good
- This transfer of electrons has a ________ effect on the size of the ions that form. - Cations are always ________ than the atoms from which they form. - Anions are always _______ than the atoms from which they form.
- Predictable - Smaller - Larger
Electrons play a key role in determining the ____________ of elements, so there should be a connection between an element's electron configuration and its _________ in the periodic table.
- Properties - Location
There are ______ rows (periods) in the table)
- Seven
- Center of square from periodic table is ______ - The ________ number for aluminum is above the symbol - The element _____ and atomic ____ are below the symbol
- Symbol - Atomic number - Element name and Atomic Mass
Each column (group) in the table has ____ labels
- Three (Scientists in the United States primarily use the labels shown in red. Scientists in Europe use the labels shown in blue.)
- Silicon can be cut into ____ and used to make computer chips - Silicon is also present as the compound _____ ______ in glass items
- Wafers - silicon dioxide
The trend is the _______ for nonmetals, like the halogens in Group 7A. For each of these elements, the ion is much _______ than the atom. As the number of electrons increases, the attraction of the nucleus for any one electron ________.
- opposite - larger - decreases
How many elements were identified in 1700?
13 elements, Chemists suspected that other elements existed. As chemists began to use scientific methods to search for elements, the rate of discovery increased
From 1765-1775 how many elements were discovered?
5
What causes sheen on freshly cleaned/cut surface?
A freshly cleaned or cut surface of a metal will have a high luster, or sheen. The sheen is caused by the metal's ability to reflect light. All metals are solids at room temperature, except for mercury (Hg).
Group 1 (1A)
Alkali Metals
Group 2 (2A)
Alkaline earth metals
Group
Column
How are trends in the weather similar to trends in the properties of elements?
Although the weather changes from day to day, the weather you experience is related to your location on the globe.
Cation
An ion with a positive charge
What are the trends for atomic number?
As the atomic number increases within a group, the charge on the nucleus increases and the number of occupied energy levels increases (these variables affect atomic size in opposite ways). And the structure of an atom changes
In a periodic table based on atomic mass, iodine should come ______ tellurium since iodine has a smaller atomic mass than tellurium does
Before
How can the behavior of metalloids be controlled?
Changing the conditions (Under some conditions, metalloids may behave like metals. Under other conditions, they may behave like nonmetals.)
What are some examples of elements that have been known for thousands of years?
Copper, silver, gold
Examples of transition metals
Copper, silver, gold, and iron are transition metals. (In atoms of a transition metal, the highest occupied s sublevel and a nearby d sublevel contain electrons. These elements are characterized by the presence of electrons in d orbitals)
The variation among nonmetals makes it _______ to describe one set of general properties that will apply to all nonmetals
Difficult (Diamond is hard, phosphorus from match heads are a brittle solid)
Are elements with similar properties found in the rows (periods) or columns (groups) of the modern periodic table?
Elements with similar properties are found in the columns, or groups, of the modern periodic table.
Why was it important for scientists to find a logical way to organize the elements?
Finding a logical way to organize the elements made it possible for scientists to determine how many elements they were looking for.
In atoms of the Group 4A elements carbon, silicon, and germanium, there are ____ electrons in the highest occupied energy level
Four
Group 7 (7A)
Halogens
The smaller the atom, the ______ the ionization energy
Higher
Period
Horizontal row
Dmitri Mendeleev
In 1869, a Russian chemist and teacher, Dmitri Mendeleev, published a table of the elements. He wrote the properties of each element on a separate note card. This approach allowed him to move the cards around until he found an organization that worked.
Describe & Illustrate how an atom becomes a cation and an anion. Use the elements Lithium and Fluorine in your example.
In collaboration space
What are the trends for atomic size?
In general, atomic size increases from top to bottom within a group and decreases from left to right across a period.
What are the trends for electronegativity values?
In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period.
In the modern periodic table, elements are arranged in order of
Increasing atomic number
Anion
Ion with a negative charge
What are the trends for ionic size?
Ionic size tends to increase from top to bottom within a group. Generally, the size of cations and anions decreases from left to right across a period.
The larger the atom, the _____ the ionization energy
Lower
What was the organization of the note cards Mendeleev used?
Mendeleev arranged the elements in his periodic table in order of increasing atomic mass.
Three classes of elements
Metals, nonmetals, and metalloids (Across a period, the properties of elements become less metallic and more nonmetallic.)
One way to think about atomic size is to look at the units that form when atoms of the same element are joined to one another. These units are called:
Molecules
Most of them are ______, but a few are ______ at room temperature, and one, ______, is a liquid
Most of them are solids, but a few are gases at room temperature, and one, bromine, is a liquid
The noble gases neon and argon produce the colors in...
Neon signs
Examples of noble gases
Noble gases
Group 8 (8A)
Noble gases
Into what four classes can elements be stored based on their electron configurations?
Noble gases, Representative elements, transition metals, or inner transition metals
Blue on table
Nonmetals
What type of element tends to form anions? What type tends to form cations? (nonmetals and metals)
Nonmetals tend to form anions. Metals tend to form cations.
In atoms of representative elements, the s and p sublevels of the highest occupied energy level are ___ _______.
Not filled
Nonmetals tend to have properties that are ________ to those of metals.
Opposite
What types of information can be included in a periodic table?
Periodic tables may contain each element's name, symbol, atomic number, atomic mass, and number of electrons in each energy level.
Each period corresponds to a
Principal energy level
Before scientists knew much about inner transition metals, people referred to them as
Rare-earth elements (This name is misleading because some inner transition metals are more abundant than other elements. Notice that some of the inner transition metals are not found in nature. These elements were prepared in laboratories)
Groups 1A-7A
Representative Elements
Mendeleev left ______ in his table sometimes
Spaces
Mendeleev placed ________ before iodine in his periodic table
Tellurium
Ionization energy
The energy required to remove an electron from an atom. (This energy is measured when an element is in its gaseous state.)
What does the period an element is located in tell you about that element's electron configuration? What does the group tell you?
The period tells you the highest occupied principal energy level. The group number is equal to the number of electrons in the highest occupied energy level.
What was the problem?
The problem wasn't with the atomic masses but with using atomic mass to organize the periodic table.
Is there more variety of properties among metals or among nonmetals?
The properties of metals are more constant. There is more variety among the properties of nonmetals.
The noble gases highest occupied energy level
The s and p sublevels are completely filled with electrons—two electrons in the s sublevel and six electrons in the p sublevel.
B elements
Transition metals
Most elements are metals, true or false
True: 80%
Example of inner transition metal
Uranium
There is a greater ________ in physical properties among nonmetals than among metals
Variation (Most nonmetals are gases at room temperature, including the main components of air—nitrogen and oxygen. A few are solids, such as sulfur and phosphorus. One nonmetal, bromine, is a dark-red liquid.)
Periodic law
When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.
Do all elements in the same period have the same number of occupied energy levels?
Yes
You are familiar with using a weather map to identify trends in the weather. For example, certain areas are typically warmer than other areas. What trends in the properties of elements can you identify with the help of the periodic table?
You can identify trends in atomic size, first ionization energy, ionic size, and electronegativity with the help of the periodic table.
All of the known elements are listed in the periodic table. What are different ways you could use the periodic table to classify elements?
You can use the periodic table to classify elements by their atomic weight, by their chemical properties, by their physical properties, or by their electron configuration.
The charge for an anion is written as
a number followed by a minus sign.
The charge for a cation is written as
a number followed by a plus sign. (If the charge is 1, the number in 1+ is usually omitted from the symbol for the ion. For example, Na1+ is written as Na+.)
As the size of the atom increases, nuclear charge has
a smaller effect on the electrons in the highest occupied energy level.
Representative elements display....
a wide range of physical and chemical properties. Some elements in these groups are metals, some are nonmetals, and some are metalloids.
Ion
atom or group of atoms that has a positive or negative charge
Positive and negative ions form when
electrons are transferred between atoms (Atoms of metals, such as sodium, tend to form ions by losing one or more electrons from their highest occupied energy levels.)
When the atoms in each molecule are identical, the distance between the nuclei of these atoms can be used to
estimate the size of the atoms (this size is expressed as an atomic radius)
Atoms of nonmetals, such as chlorine, tend to form ions by
gaining one or more electrons (In a chloride ion, the number of electrons (18) is not equal to the number of protons (17). Because there are more negatively charged electrons than positively charged protons, the chloride ion has a net negative charge.)
Metals
generally good conductors of heat and electric current. (Copper and silver are good)
Metalloid
generally has properties that are similar to those of metals and nonmetals.
Scientists use factors such as ____________ ________ to calculate values for electronegativity.
ionization energy
The properties of the elements within a period change as you move across a period from
left to right.
The electron configuration of an element can be determined based on
location of an element in the periodic table
The pattern of properties within a period repeats as you move from
one period to the next.
Atomic radius
one-half of the distance between the nuclei of two atoms of the same element when the atoms are joined
Electrons can move to higher energy levels when atoms absorb energy. Sometimes the electron has enough energy to
overcome the attraction of the protons in the nucleus.
Nonmetals
poor conductors of heat and electric current. Carbon, in the form of graphite, is an exception to this rule. - Solid nonmetals tend to be brittle, meaning that they will shatter if hit with a hammer.
It is relatively easy to remove one electron from a Group 1A metal atom, but it is difficult to..
remove a second electron. (This difference indicates that Group 1A metals tend to form ions with a 1+ charge)
Many metals are ductile, meaning:
that they can be drawn into wires
Transition metals
the Group B elements that are usually displayed in the main body of a periodic table
The increase in the number of occupied orbitals shields electrons in the highest occupied energy level from
the attraction of protons in the nucleus
Inner transition metal
the elements that appear below the main body of the periodic table (In atoms of these elements, the highest occupied s sublevel and a nearby f sublevel generally contain electrons. The inner transition metals are characterized by the presence of electrons in f orbitals.)
The energy required to remove the first electron from an atom is called
the first ionization energy.
For any representative element, its group number equals the number of electrons in the ________ occupied energy level
the number of electrons in the highest occupied energy level
Mendeleev developed his table before scientists knew about
the structure of atoms. (He didn't know that the atoms of each element contain a unique number of protons. Recall that the number of protons is the atomic number.)
Most metals are malleable, meaning:
they can be hammered into thin sheets without breaking.
He assumed that the atomic masses for iodine and tellurium were incorrect, but
they weren't! (a similar problem occurred with other pairs of elements)
Ionization energies can help you predict
what ions an element will form.