CHEMISTRY January 14, 2015 FINAL REVIEW. SCIENCE STARTER Get started on the Review. We will be going...

CHEMISTRYJanuary 14, 2015

FINAL REVIEW

SCIENCE STARTER

•Get started on the Review.•We will be going over the

questions

ANNOUNCEMENT

• FINAL EXAM ON JANUARY 16 AND 20• NO HOMEWORK ACCEPTED

AFTER JANUARY 22, 2015

SECTION 1

PROPERTIES

PERIODIC TABLE

• The Periodic Table is arranged in order of atomic number.

• Periods - the horizontal rows on the Periodic Table

• Groups/Families - the vertical columns on the Periodic Table

• There are only two elements that exist as liquid – Bromine and Mercury

QUESTION 1-3

• Which element is a liquid at STP?a) Bromineb) Cesiumc) Franciumd) Iodine

QUESTION 2-3

• The elements on the Periodic Table are arranged in order of increasing– Atomic mass– Atomic number– First ionization energy– Selected oxidation state

QUESTION 2-18

• The elements on the Periodic Table are arranged in order of increasinga) Atomic numberb) Mass numberc) Number of isotopesd) Number of moles

QUESTION 2-24

• On the modern Periodic Table, the elements are arranged in order of increasinga) Atomic massb) Atomic numberc) Mass numberd) Oxidation number

CLASSIFICATION

• METAL• NONMETAL• METALLOID

METALS

• They are solid (with the exception of mercury, Hg, a liquid).

• They are shiny, good conductors of electricity and heat.

• They are ductile (they can be drawn into thin wires).• They are malleable (they can be easily hammered

into very thin sheets).• Tend to lose electrons easily• Reacts with oxygen

NONMETALS

• Brittle, • Not malleable,• Not ductile, • Poor conductors of both heat and electricity, • Tend to gain electrons in chemical reactions. • Some nonmetals are liquids. • Some are allotropes

METALLOIDS

• The elements that border the stair-stepped line are classified as metalloids.

• Have properties that are somewhat of a cross between metals and nonmetals.

• Metalloids tend to be economically important because of their unique conductivity properties (they only partially conduct electricity), which make them valuable in the semiconductor and computer chip industry.

• Some are allotropes• List of metalloids: Boron (B), Silicon (Si), Germanium (Ge),

Arsenic (As), Antimony (Sb), Tellurium (Te), Astatine (At), Polonium (Po)

QUESTION 1-2

• The element sulfur is classified as a a) Metalb) Metalloidc) Nonmetald) Noble gas

QUESTION 1-4

• Which list of elements consists of a metal, a metalloid, and a nonmetal?a) Li, Na, Rbb) Cr, Mo, Wc) Sn, Si, Cd) O, S, Te

QUESTION 1-6

• Which element is a metalloid?a) Alb) Arc) Asd) Au

QUESTION 1-7

• A solid element that is malleable, good conductor of electricity, and reacts with oxygen is classified as a a) Metalb) Metalloidc) Noble gasd) Nonmetal

QUESTION 1-8

• An element that is malleable and good conductor of heat and electricity could have an atomic number of a) 16b) 18c) 29d) 35

QUESTION 1-9

• Which Group 14 element is a metalloid?a) Tinb) Siliconc) Leadd) Carbon

QUESTION 1-10

• The elements in Group 2 are classified as a) Metalsb) Metalloidsc) Nonmetalsd) Noble gases

QUESTION 1-11

• Which elements are malleable and good conductors of electricity?a) Iodine and silverb) Iodine and xenonc) Tin and silverd) Tin and xenon

QUESTION 1-12

• Which list of elements contains a metal, a metalloid, a nonmetal, and a noble gas?a) Be, Si, Cl, Krb) C, N, Ne, Arc) K, Fe, B, Fd) Na, Zn, As, Sb

QUESTION 1-13

• Which Group 14 element is classified as a metal?a) Carbonb) Germaniumc) Silicond) Tin

ALLOTROPES

• Allotropes: different forms of the same elements – Some elements exist in two or more forms in the

same phase– Allotropes differ in their molecular crystal

structure and their properties– Example: the allotropes of carbon are diamond

and graphite

QUESTION 1-1QUESTION 3-1

• Two forms of solid carbon, diamond and graphite, differ in their physical properties due to the differences in theira) Atomic numbersb) Crystal structuresc) Isotopic abundancesd) Percent compositions

QUESTION 1-5

• At STP, solid carbon can exist as diamond and graphite. Compared to the molecular structure and chemical properties of diamond, graphite hasa) A different molecular structure and different propertiesb) A different molecular structure and the same

propertiesc) The same molecular structure and different propertiesd) The same molecular structure and the same properties

SECTION 2

PERIODIC TABLE TRENDS

GROUP PROPERTIES

• Elements in the same group usually share similar chemical properties

QUESTION 2-4

• Which element has chemical properties that are most similar to the chemical properties of sodium?a) Berylliumb) Calciumc) Lithiumd) Magnesium

QUESTION 2-11

• Which elements have the most similar chemical properties?a) Si, As, and Teb) N2, O2, and F2

c) Mg, Sr, and Bad) Ca, Cs, and Cu

QUESTION 2-22

• Which element has chemical properties that are most similar to the chemical properties of fluorine?a) Boronb) Chlorinec) Neond) Oxygen

QUESTION 3-7

• Which list includes elements with the most similar chemical propertiesa) Br, Ga, Hgb) Cr, Pb, Xec) O, S, Sed) N, O, F

GROUP NAMES

• ALKALI METALS• ALKALINE EARTH METALS• HALOGEN• NOBLE GAS

ALKALI METALS

• GROUP 1• Usually have one valence electron• Like to give away the valence electron in a

chemical reaction• Usually forms cations

ALKALINE EARTH METALS

• GROUP 2• Usually have two valence electrons• Like to give away the valence electron in a

chemical reaction• Usually forms cations

HALOGEN

• GROUP 17• Usually have seven valence electrons• Like to receive the valence electron in a

chemical reaction• Usually forms anions

NOBLE GAS

• These elements have filled valence levels (8 valence electrons) and do not normally react with other substances.

QUESTION 2-5

• Which statement explains why neon is a Group 18 element?a) Neon is a gas at STPb) Neon has a low melting pointc) Neon atoms have a stable valence electron

configurationd) Neon atoms have two electrons in the first shell

ATOMIC RADIUS

• Atomic Radius - an estimate of the size of an atom or the distance from the center of the nucleus to the edge of the atom.

ATOMIC RADIUS - GROUP

– Atomic Radius increases from top to bottom of a Group• Reason: the number of energy levels increases as the

atomic number increases in a Group. As more energy level is added, the valence electrons are further away from the nucleus. Therefore, the atomic radius increases as the group and energy levels increase.

ATOMIC RADIUS - PERIOD

– Atomic Radius decreases from left to right across a Period. • Reason: As the atomic number increases across a single

period, the electrons are being added to the same energy level. At the same time, protons are being added to the nucleus. The concentration of more protons in the nucleus creates a "higher effective nuclear charge." In other words, there is a stronger force of attraction pulling the electrons closer to the nucleus resulting in a smaller atomic radius.

QUESTION 2-25

• An atom of which element has the largest atomic radius?a) Feb) Mgc) Sid) Zn

FIRST IONIZATION ENERGY

• First Ionization Energy - the energy required to remove the valence electron from an atom.

FIRST IONIZATION ENERGY - GROUP

– First Ionization Energy decreases from top to bottom of a Group.• Reason: As the atomic number increases in a Group,

the number of electron shells increases. As more energy level is added, the valence electrons are further away from the nucleus. Thus, the electrons are further from the nucleus and therefore easier to remove. More specifically, the number of electrons separating the valence electrons from the nucleus increases resulting in the valence electrons located in the outermost shell to be easily removed.

FIRST IONIZATION ENERGY - PERIOD

– First Ionization Energy increases from left to right across a period. • Reason: As the atomic number increases a single

period, the atomic radius becomes smaller. Since the atomic radius is smaller, the atom is smaller and the valence electrons are positioned closer to the nucleus. As a result, a stronger attraction exists between the valence electrons and the nucleus. Therefore, it becomes more difficult to remove the outermost electron.

QUESTION 2-10

• Samples of four Group 15 elements, antimony, arsenic, bismuth, and phosphorus, are in the gaseous phase. An atom in the ground state of which element requires the least amount of energy to remove its most loosely held electron?a) Asb) Bic) Pd) Sb

QUESTION 2-17

• Which atom in the ground state requires the least amount of energy to remove its valence electron?a) Lithium atomb) Potassium atomc) Rubidium atomd) Sodium atom

QUESITON 2-26

• Which element requires the least amount of energy to remove the most loosely held electron from a gaseous atom in the ground state?a) Bromineb) Calciumc) Sodiumd) Silver

ELECTRONEGATIVITY

• Electronegativity - a measure of the relative ability of an atom to attract electrons to itself.– Electronegativity decreases from top to bottom of a

Group.– Electronegativity increases from left to right across a

period. – The higher the electronegativity, the stronger the

attraction for a valence electron. In other words, the higher the electronegativity, the more likely the atom will steal the valence electrons. Most atoms with high electronegativity tend to be nonmetals.

QUESTION 2-1

• Which element has atoms with the strongest attraction for electrons in a chemical bond?a) Chlorineb) Nitrogenc) Fluorined) Oxygen

QUESTION 2-7

• Which atom has the weakest attraction for electrons in a chemical bond?a) A boron atomb) A calcium atomc) A fluorine atomd) A nitrogen atom

QUESTION 2-12

• In a bond between an atom of carbon and an atom of fluorine, the fluorine atom has a a) Weaker attraction for electronsb) Stronger attraction for electronsc) Smaller number of first-shell electronsd) Larger number of first-shell electrons

QUESTION 2-15

• Which term represents the attraction one atom has for the electrons in a bond with another atom?a) Electronegativityb) Electrical conductivityc) First ionization energyd) Mechanical energy

QUESTION 2-13

• Which statement describes the general trends in electronegativity and first ionization energy as the elements in period 3 are considered in order from Na to Cl?a) Electronegativity increases, and first ionization energy

decreasesb) Electronegativity decreases, and first ionization energy

increasesc) Electronegativity and first ionization energy both increased) Electronegativity and first ionization energy both decrease.

QUESTION 2-16

• Which general trend is found in Period 3 as the elements are considered in order of increasing atomic number?a) Increasing atomic radiusb) Increasing electronegativityc) Decreasing atomic massd) Decreasing first ionization energy

QUESTION 2-27

• Which element has the lowest electronegativity value?a) Fb) Frc) Cld) Cr

QUESTION 2-29

• What is the most likely electronegativity value for a metallic element?a) 1.3b) 2.7c) 3.4d) 4.0

METALLIC CHARACTERISTIC

• Metallic Characteristics – how readily an atom loses an electron– Metallic Characteristics increases as the atomic

number increases down a Group– Metallic Characteristics decreases as the atomic

number increases across a Period

QUESTION 2-21

• As the elements in Period 3 are considered in order of increasing atomic number, there is a general decrease in – Atomic mass– Atomic radius– Electronegativity– First ionization energy

QUESTION 2-6

• Which statement describes the general trends in electronegativity and metallic properties as the elements in Period 2 are considered in order of increasing atomic number?a) Both electronegativity and metallic properties decreaseb) Both electronegativity and metallic properties increasec) Electronegativity decrease and metallic properties

increased) Electronegativity increases and metallic properties

decrease

QUESTION 2-20

• Which general trend is found in Period 3 as the elements are considered in order of increasing atomic number?a) Increasing atomic radiusb) Increasing electronegativityc) Decreasing atomic massd) Decreasing first atomic energy

QUESTION 2-30

• Which characteristics both generally decrease when the elements in Period 3 on the Periodic Table are considered in order from left to right?a) Nonmetallic properties and atomic radiusb) Nonmetallic properties and ionization energyc) Metallic properties and atomic radiusd) Metallic properties and ionization energy

VALENCE ELECTRONS

• The outermost electrons (last number in the electron configuration) in an atom

QUESTION 2-2

• What is the total number of valence electrons in a calcium atom in the ground state?a) 8b) 2c) 18d) 20

QUESTION 2-8

• What is the total number of valence electrons in an atom of germanium in the ground state?a) 8b) 2c) 14d) 4

QUESTION 2-9

• In the ground state, which atom has a completely filled valence electron shell?a) Cb) Vc) Ned) Sb

QUESTION 2-14

• The elements in Group 2 have similar chemical properties because each atom of these elements has the samea) Atomic numberb) Mass numberc) Number of electron shellsd) Number of valence electrons

QUESTION 2-19

• Magnesium and calcium have similar chemical properties because a magnesium atom and a calcium atom have the same a) Atomic numberb) Mass numberc) Total number of electron shellsd) Total number of valence electrons

QUESTION 2-23

• An atom in the ground state has a stable valence electron configuration. This atom could be an atom ofa) Alb) Clc) Nad) Ne

QUESTION 2-28

• Compared to the atoms of nonmetals in Period 3, the atoms of metals in Period 3 havea) Fewer valence electronsb) More valence electronsc) Fewer electron shellsd) More electron shells

QUESTION 2-31

• An atom of argon in the ground state tends not to bond with an atom of a different element because the argon atom has– More protons than neutrons– More neutrons than protons– A total of two valence electrons– A total of eight valence electrons

SECTION 3

CHEMICAL BONDS

CHEMICAL BONDS

• attraction between atoms that allows the formation of chemical substances that contain one or more different atoms

ION

• an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge

CATION

• a positively charged ion

ANION

• a negatively charged ion

QUESTION 3-2

• When lithium reacts with bromine to form the compound LiBr, each lithium atoma) Gains one electron and becomes a negatively

charged ionb) Gains three electrons and becomes a negatively

charged ionc) Loses one electron and becomes a positively

charged iond) Loses three electrons and becomes a positively

charged ion

OCTET RULE

• atoms tend to combine to fill the outermost electron shell resulting in 8 valence electrons

QUESTION 3-10

• Which atom attains a stable valence electron configuration by bonding with another atom?a) Neonb) Radonc) Heliumd) Hydrogen

IONIC BOND

• bond in which one or more pairs of electrons are removed and attached to another atom, resulting in cations and anions which attract each other. Usually formed between a metal and a nonmetal

QUESTION 3-3

• In the formula XF2, the element represented by X can be classified as a a) Group 1 metalb) Group 2 metalc) Group 1 nonmetald) Group 2 nonmetal

QUESTION 3-5

• Element X reacts with chlorine to form an ionic compound that has the formula XCl2. To which group on the Periodic Table could element X belongs?a) Group 1b) Group 2c) Group 13d) Group 15

QUESTION 3-6

• The compound XCl is classified as ionic if X represents the elementa) Hb) Ic) Rbd) Br

COVALENT BOND

• bond in which one or more pairs of electrons are shared by two atoms. Usually formed between two nonmetals.

QUESTION 3-8

• What is the number of pairs of electrons that are shared between the nitrogen atoms in a molecule of N2?a) 1b) 2c) 3d) 6

QUESTION 3-9

• How many pairs of electrons are shared by the two nitrogen atoms? Given the formula for hydrazine:a) 1b) 2c) 3d) 4

ELECTRONEGATIVITY DIFFERENCE

• difference between two electronegativity values of the atoms in the compound. – Greater than 2.0 = ionic bond– Less than 1.7 = covalent bond– Between 1.7 and 2.0 = then look at classification

(metal/nonmetal) of the atom

QUESTION 3-4

• An atom of which element has the greatest attraction for electrons in a chemical bond?a) Asb) Gac) Ged) Se

TYPES OF COVALENT BOND

• Covalent bond may be separated into– Polar Bond – 0.5 or greater– Nonpolar Bond – less than 0.5

DIATOMIC ELEMENTS

• 7 diatomic atoms – hydrogen, oxygen, nitrogen, fluorine, bromine, chlorine, iodine

• HAVE NO FEAR FOR ICE COLD BEER

ELEMENT NAME

• Capitalize first letter only– Ex: H– Ex: He– Ex: Ce– Ex: Br

QUESTION 3-11

• Which substance can be broken down by chemical means?a) COb) Cec) Cad) Cu

LEWIS ELECTRON DOT DIAGRAM

• ELEMENT• IONS• IONIC BONDS• COVALENT BONDS

LEWIS - ELEMENT

LEWIS - IONS

LEWIS – IONIC BONDCompound Lewis Dot Structure

KBr

CaCl2

LiF

MgI2

LEWIS - COVALENT BOND