Chapter 5 The Periodic Table 1. ORGANIZING ELEMENTS Section 5.1 2.

transcript

Chapter 5

The Periodic Table

ORGANIZING ELEMENTSSection 5.1

A. Section 1: Organizing Elements

a. Dmitri Mendeleev was the first to design a way of organizing elements

i. Arranged elements in rows by increasing atomic masses

ii. Started a new row each time chemical properties repeated

iii. Left gaps in his list for elements that had not been discovered yet

iv. Some elements did not fit Mendeleev’s pattern

b. Henry Moseley arranged elements by atomic numbers

i. Most elements did not change their location, but a few did

c. The modern periodic table organizes elements by atomic number

d. When the elements are arranged this way, elements that have similar properties appear at regular intervals (periodic law)

e. Period: each row of the periodic table

i. There are 7 periods on the periodic table

ii. As you move to the right across a period, elements become less metallic

f. Groups: each column on the periodic table

i. each group has similar chemical properties

ii. There are 18 groups on the periodic table

Do section 1review sheet

Section 1 review

• 1. Describe how Mendeleev organized his periodic table–By increasing atomic masses–Started a new row each time chemical

properties repeated–Left gaps for undiscovered elements

Section 1 review

• 2. Explain why Mendeleev left a space for the unknown (at the time) element germanium in his periodic table.–The properties of germanium did not

match the next available group, so he moved it over to the group whose properties germanium did match, and left a space

Section 1 review

• 3. State the property used to organize elements in the modern table.–Atomic number

Section 1 review

• 4. Identify the following on the periodic table:a) The chemical symbol for mercury

b) The period and group of gold Period 6 Group 11

c) The atomic mass of iron 55.845

Section 1 review

• 4. Identify the following on the periodic table:d) The atomic number of neon

e) The element represented by Cu copper

Section 1 review

• 5. Metals conduct electricity well, while nonmetals do not. Which element should conduct electricity better: germanium, aluminum or helium?– aluminum

Section 1 review

• 6. Are the properties of sodium (Na) more like the properties of lithium (Li) or magnesium (Mg)? Explain your answer.– Lithium—they are in the same group (column)

Section 1 review

• 7. Find oxygen (O), sulfur (S), and fluorine (F) in the periodic table. Are the chemical properties of O more similar to those of S or F? Explain your answer.– Sulfur—they are in the same group (column)

What is wrong here?!!!

Section 1 review # 8

Element Symbol AtomicNumber

AtomicMass Period Group

679 196.966569Au 11

silver Ag 107.8682 5 11

calcium Ca 20 40.078

iron 26 55.845 4 8

Section 1 review• 9. If scientists found element 117, into which period and

group would they place it? Identify one element that would have properties similar to those of element 117.– Period 7, group 17– Like F, Cl, Br, I or At

REVIEWSection 5.1

matching• _____ 1. the repeating chemical & physical properties of elements change

periodically with the atomic numbers of the elements• _____ 2. a horizontal row of elements in the periodic table• _____ 3. a vertical column of elements in the periodic table• _____ 4. Mendeleev arranged the elements in rows by increasing ___ ___.• _____ 5. The modern periodic table organizes elements by ___ ___.• _____ 6. the first man to design a way to organize the elements• _____ 7. the man who arranged the elements by atomic number• _____ 8. the number of periods on the periodic table• _____ 9. the number of groups on the periodic table

• A. atomic mass B. atomic number C. 18 D. 7

• E. periodic law F. Group G. period • H. Moseley I. Mendeleev

GFABIHDC

Use the periodic table:• _____ 10. the chemical symbol for molybdenum

• _____ 11. what period is molybdenum in?

• _____ 12. what group is molybdenum in?

• _____ 13. the atomic number of molybdenum

• ____________ 14. the atomic mass of molybdenum

• _____ 15. the chemical symbol for an element that has properties similar to molybdenum

Cr, W Sg

Use the periodic table:• _____ 16. the chemical symbol for osmium

• _____ 17. what period is osmium in?

• _____ 18. what group is osmium in?

• _____ 19. the atomic number of osmium

• ____________ 20. the atomic mass of osmium

• _____ 21. the chemical symbol for an element that has properties similar to osmium

190.23

Fe, Ru, Hs

Use the periodic table:• _____ 22. the chemical symbol for platinum

• _____ 23. what period is platinum in?

• _____ 24. what group is platinum in?

• _____ 25. the atomic number of platinum

• ____________ 26. the atomic mass of platinum

• _____ 27. the chemical symbol for an element that has properties similar to platinum

195.084

Ni, Pd, Ds

3 4 5 6 7 8 9 10 11 12

13 14 15 16 17

Practice:

Periodic Table and Valence Electrons

Questions

• Definition of period– Horizontal row

• Definition of group– Vertical column

• What tells the # of valence electrons?– Group number (for 13-18, subtract 10)

• What tells the number of energy levels?– Period number

Element symbol

Period Group Number of valence e-

Number of energy levels

C 2 14 4 2

Al 3 13 3 3

Cl 3 17 7 3

Sr 5 2 2 5

Fr 7 1 1 7

Ge 4 14 4 4

Be 2 2 2 2

Se 4 16 6 430

Element symbol

Period Group Number of valence e-

Number of energy levels

Rb 5 1 1 5

Pb 6 14 4 6

P 3 15 5 3

At 6 17 7 6

F 2 17 7 2

Rn 6 18 8 6

Uuh 7 16 6 7

EXPLORING THE PERIODIC TABLE

Section 5.2

B. Section 2: Exploring the Periodic Table

a. The periodic trends in the periodic table are a result of electron arrangement

i. The chemical properties of each group are determined by the number of valence electrons

ii. The atoms of elements in the same group have the same number of valence electrons

8Number of valence electrons

Element and Symbol

Period GroupNumber of

Valence e-

Number of Energy Levels

Hydrogen, H 1 1 1 1

Nitrogen, N 2 15 5 2

Magnesium, Mg

3 2 2 3

Potassium, K

4 1 1 4

The period tells you the number of energy levels!!!

Element and

SymbolPeriod Group

Number of Valence e-

Number of Energy Levels

Iodine, I 5 17 7 5

Barium, Ba

6 2 2 6

Radium, Ra

7 2 2 7

The period tells you the number of energy levels!!!

b. Ion formation

i. Ionization: an atom may gain or lose valence electrons so its outermost energy level is full

ii. If an atom gains or loses electrons, it no longer has an equal number of electrons and protons

iii. Because the charges do not cancel completely, the atom has a net electric charge (ion)

Sodium: 11 protons 11 electronsChlorine: 17 protons 17 electrons

Sodium ion (+1): 11 protons 10 electronsChloride ion (-1): 17 protons 18 electrons

2, 8, 1 2, 8, 7

2, 8 2, 8, 8

iv. Group 1 elements

1. very reactive

2. have one valence electron which can be easily removed

3. when an atom loses an electron it becomes positiveAll of this is true of hydrogen, although it

is NOT a full member of this group!

4. positive atoms are called cations and are written with a superscript “+” next to the element symbol

5. For example, a lithium (Li) ion with a charge of +1 is written Li+ or Li1+ or Li+1

v. Group 17 elements

1. very reactive

2. have 7 valence electrons

3. needs only one more to become stable

4. when an atom gains an electron, it is called an anion, and is written with a superscript “-” next to the element symbol

5. For example: a fluorine (F) ion with a charge of -1 is written F- or F1- or F-1

vi. Other groups

1. Groups 2-16 can also form ions

2. have to lose or gain more than one electron in order to fill their outermost energy level

3. In general:

a. atoms with fewer than four valence electrons lose electrons to form cations

(positive ions)

b. atoms with more than four valence electrons gain electrons to form anions

(negative ions)

4. Ions of these elements are also indicated with superscripts, however, the symbols for these ions also show how many electrons were gained or lost

5. For example: magnesium (Mg) loses its two valence electrons to form a cation Mg2+

c. How are elements classified

i. three categories: metals, nonmetals, and semiconductors (metalloids)

Metals

Nonmetals

Semiconductors

metalloids

Three Categories of Elements

Category Properties Example

Metals good conductors of electricity and thermal energyductile (easily formed into wires) and malleable (easily shaped or formed)generally shiny solids

Nonmetals poor conductors of electricity and thermal energynot ductile or malleablegenerally not shinymay be solids, liquids, or gases

Carbon

Semiconductors

share properties with metals and nonmetalscan conduct electricity under certain circumstances

Tellurium

metalloids

Do Ion FormationPractice Sheet

Ion Formation Practice

• 1. How do we find the number of valence electrons an element has?

• Look at the group number– 1 or 2 has 1 or 2 valence electrons– 13-18: subtract 10 to get 3 – 8 valence

electrons

• 2. How many electrons can the folowing electron levels hold?– Level 1: _____– Level 2: _____– Level 3: _____

• NOTE: although level 3 can hold ___, it is full when 8 electrons are on it; all energy levels (except level 1) are full with 8 electrons!!!

• 3. If an element is giving an electron away…– a. Will the ion formed be positive or

negative?– b. will the ion be a cation or anion?

positive

cation

• 3. If an element is receiving an electron…– a. Will the ion formed be positive or

negative?– b. will the ion be a cation or anion?

negative

Ion Formation Practiceelement group

# valence electrons

electrons needed to fill outer

energy levelion formed

cation or anion?

Li 1 1 7 +1 cation

I 17 7 1 -1 anion

O 16 6 2 -2 anion

Ca 2 2 6 +2 cation

Mg 2 2 6 +2 cation

K 1 1 7 +1 cation

Ba 2 2 6 +2 cation

Cl 17 7 1 -1 anion56

element group# valence electrons

electrons needed to fill outer

energy levelion formed

cation or anion?

Sr 2 2 6 +2 cation

F 17 7 1 -1 anion

Rb 1 1 7 +1 cation

Na 1 1 7 +1 cation

S 16 6 2 -2 anion

Be 2 2 6 +2 cation

Ra 2 2 6 +2 cation

At 17 7 1 -1 anion

Fr 1 1 7 +1 cation

N 15 5 3 -3 anion57

Do section 2 review sheet

Section 2: Exploring the P.T.

• 1. Explain why elements in a group on the periodic table have similar chemical properties.

• they have the same number of valence electrons

• 2. Compare the number of valence electrons in an atom of oxygen (O) with the number of valence electrons in an atom of selenium (Se). Are O and Se in the same period or group?

• both have 6 valence electrons• they are in the same group

• 3. Explain why atoms gain or lose electrons to form ions.

• they gain or lose electrons in order to have a full outer level, which means 8 electrons (except if it’s the first level, which is full with 2 electrons)

• 4. Describe why lithium (Li) and other Group 1 elements usually form positive ions, while fluorine (F) and other Group 17 elements form negative ions.

• group 1 elements lose one electron and thus have a full outer level

• group 17 elements gain one electron and thus have a full outer level

• 5. List the three main categories of elements, and give an example of each.

• metals—Cu, Ag, Au, Sn, Al, Na, Ca• nonmetals—F, H, O, S, Ar, Br, Cl• semiconductors (metalloids)—B, Si, Ge,

As, Sb, Te, Po, At

• 6. Predict which ions cesium forms: Cs+ ions or Cs2+ ions.

• Cs+: it’s in group 1 and so gets rid of its one valence electron to form a +1 ion

• 7. Determine whether elements that fit the following descriptions are more likely to be metals or nonmetals:a) a shiny substance used to make flexible bed

springs• metal

b) a yellow powder from underground mines• nonmetal

c) a gas that does not react• nonmetal

• 7. Determine whether elements that fit the following descriptions are more likely to be metals or nonmetals:d) a conducting material used within flexible

wires• metal

e) a brittle substance that does not conduct heat

• nonmetal

• 8. Explain how a cation differs from an anion.

• a cation is a positive ion that has more protons than electrons and comes from an element losing electrons

• an anion is a negative ion that has more electrons than protons and comes from an element gaining electrons

• 9. Why do elements in groups share more chemical properties than elements in a period?

• in a group they have the same number of valence electrons and will react in the same manner either by giving or taking the same number of electrons to become stable

• 10. Why do some atoms gain electrons to form ions and some lose electrons?

• some atoms gain electrons because they have 5 – 7 valence electrons and only need 1 – 3 more electrons for a full outer level

• some atoms lose electrons because they have 1 – 3 valence electrons and will lose those in order to reveal a full outer level underneath 69

FLASHCARDSsection 2

5.2 flashcards

• The periodic trends in the periodic table are the result of ___ ___.– electron arrangement

• ion– an atom, radical or molecule that has gained

or lost one or more electrons and has a negative or positive charge

5.2 flashcards

• cation– a positive ion

• anion– a negative ion

• metal– an element that is shiny and that conducts

heat and electricity well

5.2 flashcards

• nonmetal– an element that conducts heat and electricity

poorly• semiconductor

– an element or compound that conducts electric current better than an insulator but not as well as a conductor does

• metalloid– another name for a semiconductor

QUIZ REVIEWSection 5.2

Matching • _____ 1. other name for a semiconductor• _____ 2. an element that conducts

heat/electricity poorly• _____ 3. an element that conducts electric

current better than an insulator but not as well as a conductor

• _____ 4. a positive ion• _____ 5. a negative ion• _____ 6. an element that is shiny and

conducts heat/electricity well• _____ 7. an atom that has gained or lost

one or more electrons and has a positive or negative charge

A. metalB. nonmetalC. metalloidD. semiconductorE. anionF. cationG. ion

Identify • _____ 8. ductile and malleable• _____ 9. not shiny• _____ 10. poor conductor of

heat/electricity• _____ 11. may be solids, liquids or

gases at room temperature• _____ 12. share properties with

metals and nonmetals

A. nonmetalB. metalC. metalloid

Element Group# valence electrons

Electrons needed to fill outer energy level

Ion formedCation or

Mg 2 2 6 +2 Cation

Se 16 6 2 -2 Anion

Al 13 3 5 +3 Cation

Br 17 7 1 -1 Anion

P 15 5 3 -3 Anion

K 1 1 7 +1 Cation

Ar 18 8 0 None None77

Fill-in with word bank• _____ 13. The periodic trends in the periodic

table are a result of ___ ___.• _____ 14. The chemical properties of each

group are determined by the number of ___ ___

• _____ 15. Atoms with fewer than four valence electrons ___ electrons

• _____ 16. Atoms with more than four valence electrons ___ electrons.

• _____ 17. If an element is giving an electron away, the ion formed will be ___.

• _____ 18. If an element is receiving an electron, the ion formed will be ___.

• _____ 19. Atoms gain or lose electrons in order to have a full ___ ___.

A. positiveB. negativeC. outer levelD. gainE. loseF. electron arrangementG. valence electrons

FAMILIESOF ELEMENTS

Section 5.3

C. Section 3: Families of Elements

a. Classifying elements further . . .

Group Number Number of Valence e- Name of Family

Group 1 1 Alkali metals

Group 2 2 Alkaline-earth metals

Groups 3-12 Varied Transition metals

Group 17 7 Halogens

Group 18 8 (except helium, which has 2) Noble Gases

b. Metals

i. Families of metals include alkali metals, the alkaline-earth metals, and the transition metals

zirconium

silver

ii. Alkali metals:

1. elements in Group 1

2. very reactive

not H!!!

3. valence electron can be easily removed to form a cation

4. similar physical properties: melting point, boiling point, and density

Li Na K Rb

5. Rarely found in nature as pure elements, instead they are found combined with other elements as compounds

6. For example: the alkali metal sodium (Na) is found in the salt sodium chloride, NaCl

iii. Alkaline-earth metals:

2. have two valence electrons

3. not as reactive as alkali metals

4. form cations with 2+ charges

iv. Transition metals:

1. elements found in Groups 3-12

2. not as reactive, sometimes unreactive

3. can still form ions

4. some metals can form as many as four different ions because of their complex arrangement of electrons

v. Synthetic elements

1. elements with atomic numbers greater than 92

2. made in a lab

3. radioactive and decay

4. may become different elements

5. Placed separately in the periodic table so the rest of the periodic table stays narrow, and it also allows the other elements to line up according to periodic trends

6. Have various uses

c. Nonmetals

i. Noble Gases:

2. found as single atoms rather than molecules

3. outermost energy level is filled

4. inert (unreactive)

5. very stable

ii. Halogens:

2. most reactive nonmetals

3. have seven valence electrons

4. combine easily with alkali metals

5. combinations are called salts

iodine

d. Semiconductors

i. can conduct electricity under certain circumstances

ii. Contains six elements

1. Boron 2. Silicon

3. Germanium 4. Arsenic

5. Antimony 6. Tellurium

iii. Not found in a particular group

metalloids

e. Hydrogen

i. has one valence electron

ii. Not a member of the alkali metals

iii. Most abundant element in universe

iv. Can react with many other elements

FAMILIES OF ELEMENTSSection 5.3 Review

Section 3 Review

• Classify the following elements as alkali, alkaline-earth, or transition metals based on their positions in the periodic table.– Iron (Fe)– Potassium (K)– Strontium (Sr)– Platinum (Pt)

transition

alkali

alkaline earth

transition

Section 3 Review• To which family does argon (Ar) belong?

– noble gases

• Describe why atoms of bromine (Br) are very reactive. To which family does Br belong?– Br is a member of the halogens– halogens are the most reactive nonmetals

• Which element is more reactive: lithium (Li) or beryllium (Be)? Explain your answer.– Li– alkali metals are more reactive than alkaline earth

metals100

Section 3 Review # 5Symbol Group

numberPeriod

number Family name

Co 9 4 Transition

B 13 Period 2 Semiconductor

At 17 Period 6 Halogen

Mg Group 2 3 Alkaline earth

Xe 18 Period 5 Noble gas

QUIZ REVIEWsection 5.3

periodic table

9 10 11 12

13 14 15 16

list all the alkali metals _________________________

list all the alkaline earth metals ___________________

list the metalloids ______________________________

list the nonmetals ______________________________

I F G H S J P V

list the transition metals _________________________

list the noble gases _____________________________

list the halogens _______________________________

list the elements with 3 electrons in the outer energy level __________________

B U W D C K Y

Matching• _____ 1. most reactive metals • _____ 2. metals with 2

valence electrons that form 2+ cations

• _____ 3. metals that can form as many as 4 different ions

• _____ 4. nonmetals that are nonreactive

• _____ 5. most reactive nonmetals

• _____ 6. most abundant element in the universe

A. transition metalsB. alkali metalsC. hydrogenD. halogensE. alkaline earth metalsF. noble gases

Chapter 5 The Periodic Table 1. ORGANIZING ELEMENTS Section 5.1 2.

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