The Periodic Table

Chapter 5Pg. 126-147

Organizing the Elements

Chapter 5 Section 1Pg. 126-129

The Search for Order• Until 1750, only 17

elements had been identified- mainly _____

• As the number of known elements grew, so did the need to _____ them into groups based on their ________.

• 1789, French chemist _______- grouped the known elements into categories: metals, nonmetals, gases, and earths

Mendeleev’s Periodic Table• 1860 (Russian chemist

and teacher) ________ was looking for the best way to organize the information of __ known elements

• Found a way to approach the problem while playing a version of ______ (card game)

Mendeleev’s Periodic Table

• Made a “_________” of the elements: each card had the element’s name, mass, and properties

• Also paid attention to how each element behaved in ________ with oxygen and hydrogen

• When he lined up the cards in order of _______ mass, a pattern emerged

Mendeleev’s Periodic Table• Mendeleev’s Proposal– Mendeleev arranged the elements into ____ in

order of increasing mass so that elements with _____ properties were in the same column.

– _____ arrangement: columns were organized by properties instead of suits

– Within column: the masses ______ from top to bottom

– ___________- an arrangement of elements in columns, based on a set of properties that repeat from row to row

Mendeleev’s Prediction• Could not make a complete table of the

elements because many elements had not yet been ________.

• Mendeleev left _____ in his table for the missing elements, he was confident that the gaps in his table would be filled by new elements

• He used ________ of elements located near the blank spaces in his table to _____ properties for undiscovered elements

Mendeleev’s Periodic Table

Mendeleev’s Prediction

• Mendeleev was ___ the first to arrange elements in a periodic table or leave spaces in the table for missing elements

• Mendeleev was the f____ to offer the best explanation for how the properties of an element were related to its ______ in the table

• The placement of elements on the table reveals the link between the atomic ________ of elements and their properties

Evidence Supporting Mendeleev’s Table

• Mendeleev _____ missing elements– Ex: eka-aluminum (belonged one space below

aluminum on the table) He predicted that eka-aluminum would be a soft metal with a low melting point and a density of 5.9 g/cm3

Evidence Supporting Mendeleev’s Table

• 1875- French chemist discovered a new element- named it _______ (Ga) in honor of ______– Gallium is a soft metal with a melting point of

29.7°C and a density of 5.91 g/cm3

• The close _____ between Mendeleev’s predictions and the actual properties of new elements showed how ______ his periodic table could be

The Modern Periodic Table

Chapter 5 Section 2Pg. 130-138

The Modern Periodic Table• Piano keys are in ______ (the interval

between any two notes with the same name)– octa- means eight

• Because the scale _______ at regular eight-note intervals, the scale is an example of a periodic pattern

• The sounds of musical notes that are separated by an octave are related, but they are not ________- similar to elements in columns

The Periodic Law• Mendeleev developed his periodic

table ______ the discovery of ______

• In the modern periodic table, elements are arranged by _______ atomic number (number of protons)

The Periodic Law• Periods–Each row is a _______–The number of elements per

period varies because the number of available _____ increases from energy level to energy level

The Periodic Law

The Periodic Law• Groups– Each ______ is a group– The elements within a group have ______

properties– Properties of elements repeat in a __________

way when atomic numbers are used to arrange elements into groups

– Members of a group have similar chemical properties

– Periodic ____- the pattern of repeating properties

The Periodic Law

ATOMIC MASS• Atomic mass is a value that depends on the

distribution of an element’s ______ in nature and the masses of those isotopes

ATOMIC MASS• Atomic Mass Units– The mass of an atom in grams is extremely ____

and not very useful because the samples of matter that scientists work with contain ______ of atoms

– To have a convenient way to compare the masses of atoms, scientists chose one isotope to serve as a _______

– An atomic mass unit (amu) is defined as one twelfth the mass of a carbon-12 atom

ATOMIC MASS• Isotopes of Chlorine– Most elements exist as a _____ of two or more

isotopes– There are two ______ isotopes of chlorine,

chlorine-35 and chlorine-37– An atom of chlorine-35 has 17 protons and 18

neutrons– An atom of chlorine-37 has 17 protons and 20

neutrons

ATOMIC MASS• Weighted Averages– The isotope that occurs in _____ about 75% of the

time (chlorine-35) contributes three times as much to the ______ as the isotope that occurs in nature about 25% of the time (chlorine-37)

Classes of Elements• First- elements are classified as solids, liquids,

or gases, based on their _____ at room temperature

• Black: solids• Purple: liquids• Red: gases

• Second- elements are divided into those that occur ________ and those that do not– All but 2 elements (1-92) occur on ____– Elements 93 and higher do not occur naturally

(white)

Solids, Liquids, Gases

Classes of Elements• Third- classification system puts elements into

_______ based on their general _______; elements are classified as metals, nonmetals, and metalloids– Metals: on left– Nonmetals: on right– Metalloids: in between

Metals, Nonmetals, Metalloids

Classes of Elements• Metals– _______ of the elements (blue boxes)– Good conductors of electric current and heat– ______ at room temperature (except mercury)– Most are malleable– Many are ________ (can be drawn into thin wires)– Some are extremely reactive and some do not

react easily

Classes of Elements• Metals continued…– __________ metals: metals in groups 3 through

12; form a _______ between the elements on the left and right sides of the table• one property of many transition metals is their ability

to form compounds with distinctive colors

Classes of Elements

Classes of Elements• Nonmetals– Elements that are _____ conductors of heat and

electric current– Low boiling points– Many are ______ at room temperature– Those that are solid at room temperature tend to

be ______– _______ is the most reactive nonmetal

Classes of Elements• Metalloids– Elements with properties that fall ________ those

of metals and nonmetals– Ability to conduct electric current varies with

__________• Si and Ge good insulators at low temperatures and

good conductors at high temperatures

Metals, Nonmetals, Metalloids

Variation Across a Period• _______ a period from left to right, the

elements become less metallic and more nonmetallic in their properties

• Most _____ metals are on left side of table• Most reactive nonmetals are on right side in

Group __

Representative Groups

Chapter 5 Section 3Pg. 139-149

Representative Groups• Why is Hydrogen on the left side of the

periodic table with the active metals?– It is a nonmetal ___ that seems to have more in

common with the nonmetals in Group 17• Hydrogen’s location is related to its ________

configuration, not its properties

Valence Electrons• _______ electron is an electron that is in the

highest occupied energy level of an atom– they play a key role in chemical reactions

• Properties vary across a period because the number of valence electrons ______ from left to right

• Elements in a group have similar properties because they have the _____ number of valence electrons

Valence Electrons

The Alkali Metals• Group 1– Have ______ valence electron and are extremely

reactive– Found in nature only in compounds because they

are so ______• The reactivity of alkali metals _________

from the top of Group 1 to the bottom• Sodium and potassium are stored under oil to

keep them from reacting with the ______ and water vapor in air

Alkali Metals

The Alkaline Earth Metals• Group 2– All have ___ valence electrons– Harder metals than metals in group 1

• Differences in reactivity among the alkaline earth metals are shown by the ways they react with _____

Alkaline Earth Metals

The Alkaline Earth Metals• ______________– Plays a key role in the process that uses sunlight to

produce sugar in plants– The center of _______ is magnesium– A mixture of magnesium and other metals can be

as strong as steel, but much lighter

The Alkaline Earth Metals• Calcium– Body needs calcium to keep

bones and teeth ______– Calcium _______: compound of calcium, carbon,

and oxygen- main ingredient in chalk, limestone, coral, and

pearls

The Boron Family• Group 3– All have ___ valence electrons

• __________ is the most abundant metal in Earth’s crust

THE CARBON FAMILY• Group 4– 1 nonmetal (carbon), 2 metalloids (silicon,

germanium) and 2 metals (tin, lead)– Each has ____ valence electrons

• Except for water, most of the compounds in your body contain _______

• Silicon is the ______ most abundant element in Earth’s crust

CARBON FAMILY

The Nitrogen Family• Group 5– Has 2 nonmetals (N, P), 2 metalloids (As, Sb), and

1 metal (Bi)– Wide range of _______ properties– All have ___ valence electrons– Nitrogen: nonmetal gas– Phosphorus: solid nonmetal– Bismuth: a dense metal

• Besides nitrogen, fertilizers often contain ________

Nitrogen Family

The Oxygen Family• Group 6– All have ___ valence electrons

• _______ is the most abundant element in Earth’s crust– Complex forms of life need oxygen to stay alive

because it releases the ______ stored in food– Ozone is another form of oxygen; at ground level it

is an irritant, at upper levels it absorbs harmful radiation emitted by the sun

• _______ was one of the first elements to be discovered- found in large natural deposits

Oxygen Family

The Halogens• Group 7– Each has ___ valence electrons

• Despite their physical differences, the halogens have similar _______ properties– Highly reactive _______ (fluorine most reactive,

chlorine is a close second)– React easily with most metals

The Noble Gases• Group 8– Each has ___ valence electrons with the exception

of Helium which has 2 – Colorless and _____ and extremely __________

• Some light bulbs are filled with _____ because the glowing filament in the bulbs will not react with argon as it would react with oxygen

The Noble Gases

Representative Groups