Chemistry Unit 3
The periodic table
Scientists use a hierarchical system to classify the huge variety of organisms on the planet. was developed to organize information regarding the chemical elements. - is important tool because it displays information and trends about the elements and their properties. -different types of metals such as iron, are better to use for building cars/buildings because of their strength. (wouldnt use aluminum to build a house)(other metals- silver, gold) -tin and aluminum, are soft and cant be used in the same manner. Any of these metals have different properties than gaseous elements such as oxygen or nitrogen. -continue- slide after this
atomic force microscope quantum microscope
-Atomic Force Microscope Advances in microscope technology allow scientists to obtain high-resolution images. ex- _____ uses electromagnetic repulsion to view surface properties of compounds, -scientists can now use the microscopes to image individual atoms and identify bonding between the atoms. An experimental setup called a ____ takes advantage of quantum mechanical concepts to image the electronic structure of an atom. By imaging the structure of atoms, scientists can confirm or revise our understanding of properties of elements.
Bonds
-use Lewis structures to predict bonding in a molecule, -begin with the structures of the neutral atoms. ex- consider the structures for nitrogen and hydrogen, which combine to form ammonia. -Lewis Structure for Hydrogen (pic in notes) -Lewis Structure for Nitrogen(pic in notes) Nitrogen is THREE electrons short of a complete shell hydrogen is ONE short. The combination shown gives them both complete, stable valence shells.- Ammonia Molecule The PAIRS of electrons between atoms represent ___, and the other pair, shown above the N, is a non-bonding pair. Showing bonds as a line between atoms is equivalent to showing two dots.
Dmitri Mendeleev increasing atomic mass density
1869, Russian scientist and teacher ____ attempted to arrange the 63 known elements in order of ____. working to organize the element, he also found that he could use an element's ____ to calculate the element's atomic volume. Mendelleev noted the periodicity of the volume and other noticeable repeating patterns. Some elements had distinct similarities and differences in their physical and chemical characteristics. Mendeleev's table- such a success bc he could use it to predict the chemical and physical properties of missing elements. ex- before germanium was discovered, Mendeleev used his table to predict its atomic mass, density, reactivity with oxygen, and reactivity with chlorine correctly. For these reasons, he is often called the father of the periodic table.
Rutherford
1900, ____ studied how certain elements naturally DECAY into other elements. (Radioactivity) He later developed a nuclear model of the atom. He helped confirm that the ATOMIC STRUCTURE of elements contributes to their PERIODICITY, but it also revealed a problem that the properties of some elements do not vary periodically when the elements are ordered by atomic mass. Mendeleev knew of this problem when he published his periodic table. Based on properties, he could order most elements by atomic mass, but a few he could not.
Henry Moseley Emission spectra atomic number
1913, ___, student of Rutherford's, solved this problem. he studied the emission spectra of elements. ___ are the wavelengths of light emitted by atoms that have been energized. Each element emits a DIFFERENT set of wavelengths. Studying the spectra, Moseley could determine the number of PROTONS in an atom, or the ATOMIC NUMBER, of each element. This solved Mendeleev's problem. It showed that the elements should be arranged by ___ on the periodic table, not by atomic mass. this allowed chemists to refine the periodic law. When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern.
metals, nonmetals, or metalloids
How Do Scientists Distinguish Between Metals, Metalloids, and Nonmetals? The placement of an element in the periodic table is based on ATOMIC NUMBER and ATOMIC STRUCTURE, which relates to the many properties of the element. Elements that appear in certain places on the periodic table exhibit similar properties. For example, elements can be classified as ___, ____, or ____ depending on their properties.
Periodicity Antoine Lavoisier
How and Why Did Mendeleev Organize the Elements the Way He Did? ____ is the pattern of chemical and/or physical similarities of elements that occur at regular intervals in the periodic table. Predicting the Properties of Undiscovered Elements- 1700s, French scientist ____ developed a periodic table list that separated METALS from NONMETALS. His table contained 33 elements known at the time. Just like the periodic table that is used today, early versions incorporated scientists observations about the periodic nature of elements. Periodicity is the pattern of chemical and/or physical similarities of elements that occur at regular intervals in the periodic table.
increasing atomic mass
How did Mendeleev organize elements in the periodic table?
18
How many groups are there in the periodic table? -Chart of Properties- in notes
groups families lanthanide series actinide series transition metals
Groups or Families on the Periodic Table There are 18 ___ (vertical columns) in the periodic table, which may also be called ____. The table includes 7 periods (horizontal rows). Two additional rows appear separately from the table. These elements are part of the ____ and the ___. These metals are not assigned group numbers and they have unique characteristics that make them different from the other ____.
Alkali transition
How Did Early Scientists Attempt to Organize the Elements? the early scientists who worked on organizing the elements. Early Scientists Early scientists and philosophers in ancient Greece proposed that all matter was composed of only four elements: earth, water, air, and fire. Early scientists recognized that some elements, such as metals, had similar properties and, therefore, similar uses. But they also noticed that not all metals are the same. ____ metals (such as sodium) are very reactive, while ___ metals (such as gold) are very nonreactive.
valence electrons nuclei
Like metals, the properties of nonmetals are also explained by attractions between the ____ and the ___ of the atoms. Unlike metals, nonmetals hold their valence electrons TIGHTLY. they SHARE electrons between a few atoms to make molecules. However, the molecules do NOT share electrons with each other. They are held together by WEAKER forces, which is why nonmetals often have LOW melting and boiling points. Nonmetals are brittle because the electrons do NOT flow from atom to atom. Bonds break when the atoms move. -nonmetals = low melting points
chlorine, bromine, and iodine groups
Lithium, sodium, and potassium are all metals that react strongly with water and with oxygen. Each element reacts with chlorine to produce a salt. Similarly, ___, ____, and ____ are all reactive nonmetals. Each element reacts with sodium to produce a salt. Based on the physical and chemical properties of these elements, Mendeleev placed the elements in COLUMNS now referred to as ___ or families.
Ions
__ can also be represented by Lewis structures. For example, the non-bonding electron pair in NH3 can attract a positively charged hydrogen ion to produce the stable ammonium ion, NH+4 -Ammonium Ion Lewis Structure
groups in vertical columns
What are families in the periodic table?
group number
What corresponds with the number of valence electrons in the atoms of many elements on the p-table?
noble gases grouping according to repeating patterns
Which complete group of elements was the most recent to be discovered? What is periodicity?
mostly solids, luster, high density, conductors false
Which set of properties relate to metals? True or False: Metalloids are generally all solids, shiny, brittle, and conductors and have medium density.
It was important so that elements were organized in a way that relates to their properties.
Why was it important to organize elements in the form of a periodic table?
Valence electrons
___ are an important factor in determining the PROPERTIES of an element. they are those that ATOMS tend to gain, lose, or share during a chemical reaction. The GROUP NUMBER on the periodic table corresponds with the number of valence electrons in the atoms of many elements. For representative elements, the group number GIVES the number of electrons in the outer energy level. Elements in Group 1 contain ONE valence electron. Elements in Group 2 contain TWO valence electrons. For elements in Group 13 to 18, the number of valence electrons is 10 LESS than the group number. Ex- An element in Group 15, has 5 valence electrons. (15 - 10 = 5) The elements in Groups 3 to 12 have varying numbers of valence electrons.
Lewis structure
___ is a type of shorthand for showing the details of various types of BONDS. This method is useful for showing COVALENT bonding between NONmetal atoms, as is found in most organic molecules. -also known as an electron dot diagram
groups or families vertical horizontal period number of electron energy levels
learn about groups and periods on the periodic table: Groups of the Periodic Table The periodic table includes information about all of the elements that have been discovered. Elements with SIMILAR chemical and physical properties are placed together within ___ or ____ (____ columns). Periods of the Periodic Table There are also patterns in the way elements appear within periods (___ rows). The ____ (or row) number indicates the ________ in an atom of that element.
Metalloids
only seven elements that are considered this. The metalloids appear in Groups 13 to 16. They form a jagged line between the metals and nonmetals. they exhibit properties of both metals and nonmetals. are solid at room temperature and have luster, like metals. However, metalloids are usually brittle and behave like nonmetals. video notes-
Nonmetals solid
tend to have low melting points. are more likely to exist as gases at room temperature. ____ nonmetals often exhibit properties such as brittleness(used to describe how easily something crumbles or breaks. ex- glass- breaks if dropped), poor conductivity, and dull surfaces. -Steel is not brittle and will not break if dropped.
atomic number solids right
the elements are arranged, as well as to the element type and where they are on the table. Do the same types of elements fall in the same place, or are they scattered around? some of the ways the elements are organized. The Periodic Table of Elements -Elements are listed in order of increasing _____. -Most elements are found as ___. -There are a few elements that are gases. These elements are all found on the ___ side of the table, with the exception of hydrogen. -metals are found on the left
good conductors malleable shiny not- brittle
which of the following are properties of metals?
Melting Point Metals solid
___ is the temperature at which a solid substance transforms into a liquid. ____ have high melting points. Metals are usually ___ at room temperature because of their HIGH melting points(so it takes a lot to heat them). Mercury- a highly toxic metal. It is one of only two elements that exist in the liquid state at room temperature(mercury is a liquid at room temp)
properties of elements
___ played a large role in the development of the periodic table. write what elements ur familiar with-
nonmetal elements noble gases
____ are located on the upper right-hand side of the periodic table. Atoms of most nonmetals tend to GAIN valence electrons during chemical reactions. The ___ are found in the far right column. They are STABLE and tend NOT to react with other substances. pic in notes
Semiconductors
____, a material that conducts electricity under some conditions and not others, conduct heat and electricity more easily than a nonmetal (insulator), but not as well as a metal (conductor). they are very important in the production of modern electronic devices
Metals
are located on the left-hand side of the periodic table. are primarily in Groups 1 to 12. Some elements in Groups 13, 14, and 15 are also this. (pic in notes) - any of a group of elements found in the ground, like gold, conduct heat and electricity
conductor equally
Conductors A METAL is a good ____ of heat and electricity. In solid metals, the valence electrons are shared ___ among positive metal ions. These electrons flow FREELY between the nuclei of the metal atoms. They form a sea of electrons and move easily through the outer shells of metallic atoms, which explains why metals are good conductors. However, the attraction between the positive metal ions and the sea of electrons is STRONG. This explains why most metals have high melting points. - PIC IN NOTES
physical chemical oxygen, sodium, chlorine
As more elements were discovered, scientists tried to organize the elements according to their observable ____and ____ properties. Scientists assessed physical properties: melting point, boiling point, atomic mass, density, and color. Scientists also assessed chemical properties. ex- they studied whether an element would REACT with other elements such as ___, ____, or ____. Early scientists examined how strongly an element reacted and what types of products were formed from each reaction.
four two lines six three lines
Bonds can also have more than two electrons. Double bonds have ___ electrons and are represented by ___. Triple bonds have ___ electrons and are represented by ___. Double and triple bonds are LESS flexible than single bonds. Double bonds have HIGHER bond energies and are SHORTER than SINGLE bonds. Triple bonds have even MORE energy and are SHORTER than DOUBLE bonds. -ex-diagrams show the Lewis structures for carbon dioxide and hydrogen cyanide.
eight two
For the second and third rows of the periodic table, a complete valence shell has ___ electrons, and for the first row, a complete valence shell has only ___electrons.
Johann Wolfgang Dobereiner triads three
In 1817 ____ proposed the law of ___. He arranged elements in groups of ___ based on similarities in their appearance, other physical properties, and chemical reactivity. ex- he grouped chlorine, bromine, and iodine together in a triad. Each of these elements REACTS with an alkali metal such as sodium to form a salt. He observed that the atomic mass of bromine is about HALFWAY between the masses of chlorine and iodine.
Jöns Jacob Berzelius
In 1828 ___ proposed SYMBOLS for the elements based on their Latin names. These are the same names and symbols that are used today.
increasing atomic number,
In all versions of the table, elements are placed in the periodic table according to _______ which is the number of PROTONS in an atom's nucleus. The CONFIGURATION (arrangement of elements?)of the electrons in an atom can also be predicted using the periodic table. These details about atomic structure affect the chemical and physical properties of an element.
appearance physical properties chemical reactivity chlorine, bromine, and iodine
Johann Wolfgang Dobereiner arranged elements in groups of three based on similarities in their ____, other _____, and ____ What did he group together in a triad?.- each reacts with a alkali metal to form salt
Luster
Other Properties The sea of electrons can flow with metal ions when they move. As a result, the metal ions slide past each other without breaking the bonds that hold them together. ___ refers to the shine reflected from an element's surface. Physical and chemical properties are important to consider when choosing a metal for a specific project.
Malleability, ductility, and luster Malleability Ductility
Other Properties ___, ___, and ___ also are physical properties exhibited by metals. ___ is the ability of an element to be molded into another shape without breaking or cracking. ___ is the ability of an element to be pulled into a long, thin wire.
outer Noble gases valence shell
atoms are most stable when they lose, gain, or share electrons to complete the ___, valence, shell. ____ are stable and nonreactive because their outer shell of electrons is already FULL. For the second and third rows of the periodic table, a complete ____ has EIGHT electrons, and for the first row, a complete valence shell has only TWO electrons. (inner and works outwards) -talking abt bonding
William Ramsay inert noble gases
The Modern Periodic Table 1894, ____ discovered a new group of elements called the inactive, or ____, gases. these elements today are called the ___. -Newlands had predicted these elements would be discovered. Based on their properties, the noble gases also fit into the periodic table proposed by Mendeleev.
patterns John Newlands seven law of octaves eight
These observations led to the identification of ___, which meant the properties of elements could be predicted. Around 1863, ____ proposed an early version of the periodic table that arranged the known elements in order of increasing atomic mass along rows. Each row contained ____ elements, but Newlands believed that elements would be discovered to fill an eighth spot in each row. He proposed the ____ in which elements, like notes on a musical scale, are arranged in sets of ___. This arrangement in periods, HORIZANTLE ROWS, was the FIRST OF ITS KIND.
gain, lose, or share
Valence electrons produce many of the familiar properties of metals. Most metals are quite reactive because they easily ____, _____, or ____ VALENCE ELECTRONS. Metals are typically conductive, malleable(able to be pressed permanetly out of shape without breaking it), and ductile(not brittle), and they have shiny surfaces. - more about these properties: -metals are reactive
