Matter and the Periodic Table

Editor: Jessen Foster

Matter is defined as something that occupies space and can be perceived by one or more senses. Like chemistry being the base science, matter is the base for everything. Everything in our universe is made of matter, whether it be the pens we use in school or the keyboard I am typing on right now.


Periodic Table:

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GROUP 1

Co-Editor: Bryan Dextradeur

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Group Members: Kayla Anghinetti, Bryan Dextradeur, Ellie Kawa, Neal McGovern, David Monti

Ellie Kawa

Properties of Matter (pgs 39-43)

Describing Matter

  • Properties used to describe matter can be classified as intensive or extensive
  • Mass- a measure of the amount of matter the object contains
  • Volume- a measure of the space occupied by the object
  • Mass and volume are examples of extensive properties
  • Extensive property- a property that depends on the amount of matter in a sample
  • Hardness is an example of an intensive property
  • Intensive property- a property that depends on the type of matter in a sample, not the amount of matter

Identifying Substances

  • Substance- matter that has a uniform and definite compositionexternal image copper+kettle.jpg
  • Gold and copper are examples of substances (also known as pure substances)
  • Every sample of a given substance has identical intensive properties because every sample has the same composition
  • Hardness, color, conductivity, and malleability are examples of physical properties
  • Physical property- a quality or condition of a substance that can be observed or measured without changing the substance’s composition
  • Physical properties can help chemists identify substances

States of Matter

Water, a common substance, exists in three different ways

  • external image 200px-SolidState.pngThe three states of matter are solid, liquid, and gas
  • Solid- a form of matter that has a definite shape and volume
  • The particles in a solid are packed tightly together, often in an orderly arrangement
  • Solids are almost incompressible (it is difficult to squeeze a solid into a smaller volume)
  • Solids expand only slightly when heated
  • The particles in liquid are in close contact with one another, but the arrangement of particles in a lexternal image 200px-LiquidState.pngiquid is not rigid or orderly
  • A liquid takes the shape of its container
  • The volume of a liquid is fixed or constant
  • Liquid- a form of matter that has an indefinite shape, flows, yet has a fixed volume
  • Liquids are almost incompressible, but they tend to expand slightly when heated
  • A gas takes the shape of its container; it can expand to fill any volumeexternal image 200px-GaseousState.png
  • Gas- a form of matter that takes both the shape and the volume of the container
  • The particles in gas are usually much farther apart than the particles in a liquid
  • Gases are easily compressed into a smaller volume
  • “Gas”- used for substances that exist in the gaseous state at room temperature
  • Vapor- describes the gaseous state of a substance that is generally a liquid or a solid at room temperature (water vapor)

Physical Changes

  • Melting is an example of a physical change
  • Physical change- come properties of the material change, but the composition of the material does not change
  • Boil, freeze, melt, condense external image matter_intro_2_240.gif
  • Break, split, grind, cut, crush
  • Each set describes a different type of physical change
  • Physical changes can be classified as reversible or irreversible
  • Melting is an example of a reversible physical change
  • All physical changes that involve a change from one state to another are reversible
  • Cutting hair, filing nails, and cracking an egg are examples or irreversible physical change



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David Monti

Mixtures (Pages 44 - 47)

Classifying Mixtures
- Mixture – A physical blend of two or more components
- Most samples of matter are mixtures, some are easier to recognize than others ex: Mixture of ingredients in chicken soup is easy, mixture of
gasses in air is difficult.
campbells-soup-i-chicken-noodle-c1968-premium-giclee-print-c12985614.jpg air1_sm.jpg

- Based on the distribution of their components, mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures
- Heterogeneous Mixtures – A mixture in which the composition is not
uniform throughout. Ex. Chicken Soup
- Homogeneous Mixtures – A mixture in which the composition is uniform
throughout. Ex: Air, olive oil, vinegar
1. Also called a solution (mostly liquids)
2. Phase – a term used to describe any part of a sample with uniform
composition and properties, heterogeneous has many phases, homogeneous has one phase

Separating Mixtures

- Example problem – Separating a mixture of aluminum nails and iron nails:
Aluminum Iron
Metal Metal
Gray color Gray color
Doesn’t dissolve
In water
Not attracted to
Attracted to metal
Magnet
Solution: Magnet
- Separating can be accomplished through many different methods
- Differences in physical properties can be used to separate mixtures
- Filtration - The process that separates a solid from the liquid
- Distillation – The process to separate homogeneous mixtures which involves
boiling liquid, collecting vapor, and condensing it into a separate liquid


Neal McGovern (48-49)

Distinguishing Elements and Compounds

-two types of substances-elements, compounds

-an element is the simplest form of matter with a unique set of properties
-a compound is a substance made of two or more elements chemically combined in a fixed proportion

Breaking Down Compounds

-physical methods cannot break down compounds

-chemical change is a change that produces matter with a different composition than the origional
-example- heating water, which is a physical method, doesn't break down water. On the other hand, an electric current will. When an electric current goes through water, hydrogen gas and oxygen gas, two elements, are released.

Properties of Compounds

-properties of compounds are quite different from those of their component elements

-for example, Sodium is a soft, gray metal, while Chlorine is a pale-yellow-green poisonous gas. Meanwhile, Sodium-chloride, salt, is a white solid

Kayla Anghinetti

Section 2.3, p.50-52

Distinguishing Substances and Mixtures

- By using general characteristics, you can distinguish substances from mixtures.

- If the composition of a material is fixed, it is a substance.
- If the composition of a material may vary, it is a mixture.

Symbols and Formulas

- Chemists use chemical symbols to represent elements

- Chemical formulas are used to represent compounds
- Symbols used today are based on a system developed by Jons Jacob Berzelius, a Swedish chemist
- Each element is represented by a one or two letter chemical symbol
- First letter is always capitalized, second letter is always lowercase.
- Subscripts in chemical formulas, such as H2O, are used to indicate the relative proportions of the elements in the compound
-The subscript 2 in H2O indicates that there are two parts of hydrogen for each part of oxygen in water.
- Because a compound has a fixed composition, the formula for a compound is always the same.

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Practice!

Problems:

1. A clear liquid in an open container is allowed to evaporate. After three days, a solid is left in the container. Was the liquid an element, compound or mixture? Why?
2. Liquid A and Liquid B are clear liquids. They are placed in open containers and allowed to evaporate. When evaporation is complete, there is a white solid in container B, but no solid in container A. From these results, what can you infer about the two liquids?

Worksheets:
1.http://docs.google.com/viewer?a=v&q=cache:8fJ6zLiwuhMJ:staff.fcps.net/jswango/unit1/chap1/matter% 2520packet.pdf+elements+compounds+mixtures+worksheets&hl=en&gl=us&pid=bl&srcid=ADGEESjWH6FSh8f-s01mXgcKOWbKRKgrA2ngB2XJdeZP2tGpREMToOUMc2Qlk_8CxJjBV-mS-qjrQzpeo1_DNV6hvchgBCtQDxzNVbDXxE8ONUTY6sl-Qp1kGsQHRCl9DLDkAcyt4kzl&sig=AHIEtbThTFoAsydDsnMm0PyQMiDYpaVO6w
2. http://www.teach-nology.com/worksheets/science/element/
Quizzes:
http://www.funbrain.com/periodic/index.html
http://education.jlab.org/elementflashcards/index.html

Chemical Reactions (Pages 53-55)

BY: Bryan Dextradeur


Chemical Changes

Chemical Property: The ability of a substance to undergo a specific Chemical Change.

Example: Iron is able to combine with oxygen to form rust, so the ability to rust is a chemical property of iron.

  • Words such as burn, rot, rust, decompose, ferment, explode, and corrode usually signify a chemical change.
  • During a Physical Change, the composition of matter never change (the substances present before the change are the same substances present after the change).
  • During a Chemical Change, The composition of matter always changes.
Example: A magnet being used to separate iron from sulfur is a physical change because the iron and the sulfur stay the same, they are just not physically blended anymore.

Example: If a mixture of iron and sulfur is heated, a chemical change occurs because the iron and the sulfur react to form iron sulfide (FeS) .

  • A Chemical Change is also called a Chemical Reaction.
  • During a Chemical Reaction, one or more substances change into one or more new substances.
  • A Reactant is a substance present at the start of the reaction.
  • A Product is a substance produced in the reaction.
Example: In the reaction of iron and sulfur, iron and sulfur are reactants and iron sulfide is the product.

Recognizing Chemical Changes
  • There are four main clues that indicate Chemical Change.
  • Possible clues to Chemical Change include a transfer or energy, a change in color, the production of a gas, or the formation of a precipitate.
  • Every Chemical Change involves a transfer of energy.
Example: Energy in the form of natural gas is used to cook food. When methane from natural gas combines with oxygen in the air, energy is given off in the form of heat and light, some of which is absorbed by the food cooking over the burner.
  • A Precipitate is a solid that forms and settles out of a liquid mixture.
Example: Soap Scum forming on bathtubs and sinks is a precipitate
  • If a clue to a chemical change is observed, it is still not certain that a chemical change has taken place; the clue may be the result of a physical change.
  • The only way to be sure that a chemical change has occurred is to test the composition of a sample before and after a change.
Example: Transfer of energy, a clue to a chemical change, also occurs in a change in matter from one state to another, which is a physical change.

Conservation of Mass
  • During any Chemical Reaction, the mass of the products is always equal to the mass of the reactants.
  • The amount of matter is unchanged during a chemical reaction.
Example: When wood is burned, a sizable amount of matter is reduced to a small pile of ashes. However, two of the products of burning wood, carbon dioxide and water vapor, are released into the air, and when the mass of these gases is measured, the amount of matter before and after the experiment is unchanged.
  • Mass also holds constant in a Physical Change.
Example: 10g of ice melts to 10g of liquid which boils to 10g of gas.
  • The Law of Conservation of Mass states that in any Physical Change or Chemical Reaction, mass is conserved.
  • Mass is neither created nor destroyed.



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GROUP 2

co-editor: Lindsey Chou

Emily Stewart, Hannah Kumlin, Shannon Leavey, Nikki Sheehan




Searching For an Organizing Principle (p 155)

Emily Stewart


By the year 1700, only 13 elements had been identified, but chemists suspected that more existed. As scientific methods were used and more elements were discovered, it became necessary to organize the elements in some way.
Chemists used the properties of elements to sort them into groups.
- In 1829, J.W. Dobereiner published a classification system.
- elements grouped into triads - set of 3 elements with similar properties
- example: they react easily with metals
- not all elements could be grouped into triads, and this system turned out not to be very useful
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Mendeleev’s Periodic Table (p156)

Emily Stewart



Many different systems were proposed from 1829-1869, but none of them gained wide acceptance.
Dmitri Mendeleev published a table of the elements in 1869.
Lothar Meyer published a very similar table later that year.
Mendeleev got more credit - he published it first & did a better job explaining its usefulness
Mendeleev’s table:
- shows relationships among more than 60 elements
- shows elements in order of increasing atomic mass
- has question marks to show where undiscovered elements might fit in
- sure enough, newly discovered elements matched his predictions
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Periodic Law (p. 157)

Hannah Kumlin

- Mendeleev continued to sort the elements by their increasing atomic masses, but he soon encountered a problem.

- The atomic mass of iodine (I) is 126.90 and the atomic mass of tellurium (Te) is 127.60, but based on its chemical properties, iodine belongs in a group with bromine and chlorine. So, Mendeleev had to break his rule and placed tellurium before iodine in his periodic table. He believed that he miscalculated their atomic masses, however they were correct.
- A similar problem occurred with other pairs of elements.
- Mendeleev discovered that the problem was not with the atomic masses, but with using atomic masses to organize the periodic table.
*Mendeleev developed his table before scientists knew about the structure of atoms in elements.
-In 1913, Henry Moseley, a British physicist, determined an atomic number for each element.
*An element's atomic number is the number of protons the element contains in it's nucleus.

-In the modern periodic table, elements are arranged in order of increasing atomic number.




Here's today's version of a periodic table:

external image moz-screenshot-5.pngPeriodic_Table.JPG


OR click HERE! for another picture and more information on the elements of the periodic table.

-There are seven rows/periods in the table.
-There are more elements in higher numbered periods because there are more orbitals in higher energy levels. (See Chapter 5, pg. 131 for more information on atomic orbitals)
-The elements within a column, or group, in the periodic table have similar properties. The properties of elements within a period change as you move left to right, however, the pattern of properties within a period repeats as you move from one period to the next.

-This pattern gives rise to the Periodic Law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

Lindsey Chou
Metals, Nonmetals and Metalloids (158-160)
o Scientists need to agree on the standards they use in order to have clear communication
o The IUPAC (International Union of Pure and Applied Chemistry) sets chemistry standards, like the labeling of the groups in the periodic table
o The elements of the periodic table can be grouped based on their properties
o The three classes of elements are metals, nonmetals and metalloids

Metals

o About 80% of elements are metals
o Metals are good conductors of heat and electrical currents
o All except mercury are solids at room temperature (21 )
o Many metals are ductile (can be made into wires) and/or malleable (can be made thin without breaking)
o Shown in the green section of this periodic table

Nonmetals

o Listed in the upper right corner of the periodic table (orange section of this periodic table)
o Not metals, so they often have the opposite properties of a metal – such as poor heat conduction (carbon is the exception)
o Most are gases at room temperature, although some are solids are liquids as well

Metalloids

o Properties of metalloids are similar to the properties of metals and nonmetals
o Depending on the situation, a metalloid may behave like either a metal or nonmetal
Ø Example: Silicon is a poor conductor (like a nonmetal) in its pure form, but with a small amount of boron it is a very good conductor (like a metal)
o Shown in the blue section of this periodic table


periodic_table_sm.gif


Shannon Leavey

Classifying the Elements (pages 161-164)




Squares in the Periodic Table

  • The periodic table displays the symbols and names of the elements, along with information about the stucture of their atoms
  • external image gcsechem_71.gif
  • Atomic number
    Element symbol
    Element name
    Average atomic mass


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ELECTRON CONFIGURATIONS IN GROUPS

-elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations



Noble gases
Example: helium

-noble gases are the elements in group 8A of the periodic table
-also called inert gases because they rarely take part in a reaction
electron configurations for first four noble gases:
Helium (He)
1s2
Neon (Ne)
1s22s22p6
Argon (Ar)
1s22s22p63s23p6
Krypton (Kr)
1s22s22p63s23p63d104s24p6


Nikki Sheehan (164-166)**


Representative Elements

-elements in the portion of the periodic table containing groups 1A through 7A
-they are known as representative elements because they display a wide range of physical and chemical properties
-some are metals, some are non-metals, some are metalloids
-most are solids, few are gases, one is a liquid
-for any representative element, its group number equals the number of electrons in the highest occupied energy level

Transition Elements

-elements in the B groups which provide a connection between the two sets of representative elements
-examples of transition metals-copper, silver, gold, iron
-in the 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
-in the atoms of an inner transition metal, the highest occupied S sublevel and nearby F sublevel generally contain electrons
-these elements are characterized by F orbitals contain electrons
-inner transition metals used to be known as rare-earth elements (misleading because some I.T metals are more abundant than other elements)

Blocks of Elements

-periodic table is divided into sections, or blocks
-these correspond to the highest occupied sublevels
-S block contains elements in groups 1A and 2A and the noble gas helium
-P block contains elements in groups 3A, 4A, 5A, 6A, 7A, and 8A (with the exception of helium)
-D block contains transition metals
-F block contains inner transition metals
-each period on the periodic table corresponds to a principal energy level

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GROUP 3

Periodic Trends

Co-editor: Elena Conroy

Lauren Murphy, Chris Kelly, Teresa Lynch

Trends in Atomic Size and Ions (pages 170-172)

By: Lauren Murphy

Atomic Size:

-one half of the distance between the nuclei of two atoms of the same element when the atoms are joined
-measured in picometers

Group Trends in Atomic Size:

-as the atomic number increases within a group, the charge of the nucleus increases/number of occupied energy levels increases
-variables affect atomic size in opposite ways
-increase in positive charge pulls electrons closer to nucleus
-increase in occupied orbitals shields electrons in the highest energy level from the attractions of protons to the nucleus
-shielding affect is bigger than the effect of the increase in nuclear charge
-in general, atomic size increases from top to bottom within a group

Periodic Trends in Atomic Size:

-across a period, electrons are added to the same principal energy level
-shielding affect is constant for all elements in a period
-increasing nuclear charge pulls electrons in the highest energy level closer to the nucleus
-in general, atomic size decreases from left to right across a period

Ions:

-positive and negative ions form when electrons are transferred between atoms
-an ion with a positive charge is called a cation (+)
-a positive charge happens when there are more positively charged protons than negatively charged electrons
-an ion with a negative charge is called an anion (-)
-a negative charge happens when there are more negatively charged electrons than positively charged protons

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-Atomic size increases from right to left and increases from top to bottom.
http://www.grandinetti.org/Teaching/Chem121/Lectures/AtomicRadii/assets/radiitable.gif


Trends in Ionization Energy (pages 173-176)

By: Teresa Lynch


Ionization Energy

-the energy required to remove an electron from an atom.
-measured in a gaseous state
-1st ionization energy= energy required to remove the first electron
-tends to decrease from top to bottom within a group and increase from left to right across a period
-the cation produced has a 1+ charge
-2nd ionization energy=the energy required to remove an electron from an ion with a 1+ charge
-produces an ion with a 1+ charge
-3rd ionization energy=energy required to remove an electron from an ion with a 2+ charge
-produces an ion with a 3+ charge
-Ionization energy can help you predict what ions elements will form.

Group trends in Ionization Energy:

-As the atomic size increases as the atomic number increases within a group
-As the size of the atom increases, nuclear charge has a smaller effect on the electrons in the highest occupied energy level. So less energy is required to remove an electron from this energy level= 1st ionization energy is lower.

Periodic Trends in Ionization Energy:

-1st ionization energy of representative elements tends to increase from left to right across a period.
-this is because the nuclear charge increases but the “shielding effect” remains constant.
-it takes more energy to remove an electron from an atom

Trends in Ionic Size:

-in reactions between metals and nonmetals: metals lose electrons and nonmetals gain them.
-Cations are always smaller than the atoms from which they form. Anions are always larger than the atoms from which they form.
-representative metals lose their outermost electrons during ionization. So ion has one fewer occupied energy level.
-the trend is opposite for nonmetals.

external image fig3.png
This graph represents first ionization energy versus atomic number. In the periodic table, ionization energy generally increase from left to right and decrease from top to bottom.
http://cnx.org/content/m12433/latest/fig3.png


Electronegativity

By: Chris Kelly

  • Electronegativity is the ability of an atom of an element to attract electrons when the atom is in a compound.
  • Electronegativity is also a property used to predict the type of bond that will form during a reaction.
  • Ionization energy is used to calculate values for electronegativity
  • Noble gases are omitted from electronegativity values because they do not form many compounds.
  • the units are called Paulings
  • Linus Pauling was the first to define electronegativity
  • He won Nobel Prize in Chemistry for work on chemical bonds
  • Generally, values for electronegativity decrease form top to bottom in a group
  • Representative elements increase left to right in a period
  • Metals at the far left have low values
  • Nonmetals at the far right have high values
  • The least electronegative element is cesium (0.7)
  • The most electronegative element is fluorine (4.0)
  • The trends that exist among atomic size, ionization energy, ionic size, and electonegativity can be explained by variations in atomic structure.

external image PT-small-electroneg.gif
This chart states the eletronegativity of the elements in the periodic table.
http://www.green-planet-solar-energy.com/images/PT-small-electroneg.gif
Formating and pictures done by: Elena Conroy