Unit 4: The Periodic Tableand Periodicity

Chemistry

OutlineOutline

The Elements

elements known to the ancients…

Element names come from a variety of sources.

place names…

famous people…

foreign languages…

mythology-related names…

names related to element properties…

S, Cu C, Sn,

Fr, Po, Ge, Eu, Am, Cf, Sc

Es, Md, No, Rf, Bh

Hg

TiTh,

W, Fe, Au, Ag, Pb, Cu

atomic number

Background on the Periodic Table

Dmitri Mendeleev: given creditfor Periodic Table (~1870)

--

--

organized Table byincreasing atomic mass left spaces and predictedproperties of undiscoveredelements

Henry Moseley: put elements inorder of increasing____________.

Mendeleev

Moseley

Describing the Periodic Table

periodic law: the properties of elements repeat every so often

period:

group (family):

horizontal row; there are 7

vertical column; there are 18 18

1716151413

129 10 1187654

1

3

21

2

34

6

7

5

Regions of the Table

metals: left side of Table; form cations

properties:

lustrous(shiny)

ductile(can pullinto wire)

malleable(can hammerinto shape)

good conductors(heat and electricity)

nonmetals: right side of Table; form anions

properties: good insulatorsgases or brittle solids

Regions of the Table (cont.)

Br2I2S8Ne

bromineiodinesulfurneon

computer chips

metalloids (semimetals): “stair” between metalsand nonmetals

properties: in-between those of metalsand nonmetals; “semiconductors”

Regions of the Table (cont.)

(B, Si, Ge, As, Sb, Te, Po)

Si and Ge

computer chips

metals

nonmetals

alkali metals:

alkaline earth metals:

halogens:

noble gases:

contain f orbitals

lanthanides:

coinage metals:

transition elements:main block (representative) elements:

group 1 (except H); 1+ charge;very reactive

group 2; 2+ charge;less reactive than

alkalisgroup 17; 1– charge; very reactive

group 18; no charge; unreactive

elements 58–71

actinides: elements 90–103

group 11 (part of the transition metals)

groups 3–12; variable charges; d block

groups 1, 2, 13–18; s and p block

alkaline earth metals

halogensnoble gaseslanthanides

alkali metals

actinides

coinage metals (part of the transition metals)

transition elements

main block elementsmetalloids

hydrogenmore nonmetals

more metals

Honors

• Trans-uranic Elements• Elements with an atomic number greater than 92.

www.chemicool.com

• Complete data table as a group of two, defend your decision using the form. You may write your defense in essay form if needed. Be specific and answer all guiding questions.

• Due next Wednesday, Jan. 15, 2014

Einsteinium (Es)

Albert Einstein– Relativity– E = mc2

– Offered Presidency of Israel– Element 99– Photoelectric effect

• Solar calculator

Curium (Cm)

• Madame Curie– Pioneer in radioactivity

• (Ra = radium)– 25 pounds of pitchblende ore

yields 1/1000 of a gram of radium– Emits 2 millions times as much

radiation as uranium

• (Rn = radon gas)

– Discovered 5 elements– Nobel Prize (5 in Curie family)

– Born in Poland • (Po = polonium)

Marie Curie (1876–1934)

Radium (Ra)

Radium was used as a fluorescent paint on watch dials. It wasapplied with thin brushes that workers would lick to keep a fine tip. Many people died from the exposure to radium.

Radon Gas

Radon gas occurs naturallyfrom the radioactive decayof radium. Radium is found in small amounts in rock.

Ra Rn + radiation

Predicted fraction of homes over 4 picocuries/liter radon

Zone 1 counties have a predicted average indoor radon screening level greater than 4 pCi/L (pico curies per liter) (red zones)

Zone 2 counties have a predicted average indoor radon screening level between 2 and 4 pCi/L (orange zones)

Zone 3 counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones)

http://www.epa.gov/radon/zonemap.html

Nobelium (No)Element 102

Alfred Nobel

Nobel PrizeInventor: dynamite (TNT) blasting gelatin

“Merchant of Death”

CH3

NO2

NO2O2N

Trinitrotoluene

Seaborgium (Sg)

Glenn Seaborg– Separated f-block from rest of periodic table– Worked on Manhattan Project

(Atomic bomb)– Classified until after WW II– Element 106

• Only living person to have an element named for them

Silicon vs. Silicone

• Silicon (Si) element• Silicone (…Si – O – Si…) polymer

– Sealant (caulk) prevents leaks

– Breast augmentation

No cause-and-effect relationship exists between breast enlargement and breast cancer. Only oneresearcher found a causal link.

Magnesium

Atomic Mass 24 amumelting point = 650oC (1202oF)

silver gray metal

used in flash bulbs, bombs,and flares8th most abundant element (2.2% of Earth’s crust)

lack of Mg produces same biological effect as alcoholism (delirium tremens)

Mg24.305

12

Mendeleev’s Work!

• http://www.screencast.com/t/kg5WRCqrqcUh

Periodicity

The quality of being periodic; tendency to recur at regular intervals.

Electro negativity

Tendency of an atom to attract electrons towards itself.

Same number of valence e– =

Li Na

In any group, the element BELOW has one moreoccupied energy level than does the element ABOVE.

Li Na

similar properties

1s2 2s1 1s2 2s2 2p6 3s1

The period that an element is in is the same as theenergy level that its valence electrons are in.

Li Na

v.e– in 2nd E.L. v.e– in 3rd E.L.

in 3rd periodin 2nd period

Periodicity

there are trends in properties of elements

-- left-right AND up-down trends

atomic radius: the size of a neutral atom

add a new energylevel each time

WHY?

…increases as we go

…decreases as we go

WHY?

coulombic attraction: attraction between (+) and (–)

it has to do with…

Coulombic attraction depends on…

2– 2+

2+ 2– 1–

2–

1+

2+

amount of charge distance between charges

+ + – –

H

He

+ –

+ – + –

As we go , more coulombic

attraction, no new energy level, more pull, smaller size

shielding effect: kernel e– “shield” valence e–

from attractive force of the nucleus

Li v.e–

K v.e–

-- caused by kernel and valence e–

repelling each other

As we go , shielding effect increases.

tougher to remove

easierto remove

ionic radius:

cations anions

Ca atom Ca2+ ion Cl atom Cl1– ion

the size of an ion

20 p+

20 e–

20 p+

18 e–

17 p+

17 e–

17 p+

18 e–

Ca Ca2+ Cl Cl1–

cations are smaller anions are larger

ionization energy: the energy required to remove an e– from an atom

M + 1st I.E.

M + 2nd I.E.

M + 3rd I.E.

As we go , 1st I.E….

As we go , 1st I.E….

M1+ + e–

M2+ + e–

M3+ + e–

removes 1st e–

Each successive ionization requiresmore energy than the previous one.

decreases.

increases.

(due to the shielding effect)

electronegativity:

Linus Pauling quantifiedthe electronegativity scale.

the tendency fora bonded atom toattract e– to itself

As we go , electronegativity…

As we go , electronegativity…

decreases.

increases.

electronegativity increases

Summary of Summary of Periodic TrendsPeriodic Trends