chemistry chapter 5
DESCRIPTION
Chemistry Chapter 5. The Periodic Table. Sept 1860, group of chemists met in Germany to review scientific matters & coming to consensus about: measurement of atomic masses determining composition of compounds using atomic masses - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/1.jpg)
The Periodic Table
ChemistryChapter 5
![Page 2: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/2.jpg)
![Page 3: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/3.jpg)
Sept 1860, group of chemists met in Germany to review scientific matters & coming to consensus about:measurement of atomic massesdetermining composition of
compounds using atomic masses
Cannizzaro presented method for measuring mass & scientists agreed upon the std values for atomic masses
![Page 4: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/4.jpg)
in 1869, Dmitri Mendeleev used Cannizzaro’s method for measuring relative masses of atoms in textbook he wrote
published the arrangement of elements in – periodic table
![Page 5: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/5.jpg)
only 60 elements known at this time
organized elements acc to properties & new atomic masses on cards
“game of patience”Mendeleev grouped elements according to incr atomic mass & noticed certain properties appeared at regular intervals- periodic
![Page 6: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/6.jpg)
![Page 7: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/7.jpg)
in 1871, Mendeleev predicted properties of elements that weren’t even discovered at that time!
not all elements fit in according to increasing atomic mass:I & Te Ar & K Co & Ni
Mendeleev couldn’t explain whyother scientist accepted the
periodic table & considered him the Father of the Periodic Law
![Page 8: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/8.jpg)
![Page 9: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/9.jpg)
in 1913, Henry Moseley discovered patterns w/ x-ray tubes that led to atomic number (ch 3 notes)
he noticed that when he reordered elements on table acc to incr atomic number they fit into their patterns in better way
led to the Modern periodic table
periodic law- phy & chem properties of the elements are periodic functions of the atomic #
![Page 10: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/10.jpg)
Getting Acquainted
With the Periodic Table
![Page 11: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/11.jpg)
valence e- same for all elements in group
group 1: Alkali metals e- conf: ns1
group 2: Alkaline Earth metalse- conf: ns2
groups 3-12: Transition metalse- conf: (n-1)d1ns2
Group Properties
![Page 12: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/12.jpg)
groups 4-11 deviations occursum of outer s & d e- equal to group
#
group 13: ns2np1
group 14: ns2np2
group 15: ns2np3
group 16: ns2np4
group 17: Halogens ns2np5
group 18: Noble gases ns2np6
![Page 13: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/13.jpg)
noble gases have 8 valence e-
have stable octet very stable & unreactive
f-block elementslanthanides- rare earth metals 1st row
actinides- all radioactive; most synthetic
![Page 14: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/14.jpg)
phy & chem properties vary in periodic fashion
properties arise from e- configuration
5 properties:
Periodic Properties
![Page 15: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/15.jpg)
½ distance betw nuclei of identical atoms joined in a molecule
e- occupy large region around nucleus & size atom varies
periodic trends- gradual decrease in radii across periodsdue to increasing pos chrg of nucleus
(pulled tighter by nucleus)
1. Atomic Radii
![Page 16: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/16.jpg)
group trends: as go down group, atomic radii increases due to addition of e- to larger orbitals in higher energy levels
![Page 17: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/17.jpg)
![Page 18: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/18.jpg)
minimum amount of energy required to remove the most loosely bound e- from an isolated gaseous atom to form an ion w/ a +1 charge
if enough energy is supplied, e- can be removed from atoms
ex: 1st IE for Ca is 590 kJ/mol
Ca + 590kJ/mol Ca+ + e-
2. Ionization Energy
![Page 19: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/19.jpg)
ionization- process that results in the formation of ion
2nd IE is 1145kJ
IE2 > IE1ALWAYS more difficult to remove additional e- from positive ion
IE measures how tightly e- are bound to atoms
![Page 20: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/20.jpg)
low IE indicates ease of e- removal & cation formation
group trends: as atomic radii increases in a group, 1st IE decreases b/c the valence e- are further
from nucleus “shielding effect”
period trends: IE incr from L to R due to increasing nuclear charge which holds e- tighter
![Page 21: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/21.jpg)
nonmetals tend to have higher IE than metals
![Page 22: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/22.jpg)
amount of energy involved in the process in which an e- is added to an isolated gaseous atom to produce an ion w/ a -1 charge
many atoms readily add e- & release energyex: Cl + e- Cl- + energy
(exothermic)
Why?
3. E- affinity
![Page 23: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/23.jpg)
some have to be forced to gain e- by the addition of energyBe + e- + energy Be-
period trends: group 17 elements gain e- most easily ( large neg values) reason for the reactivity of these halogens
![Page 24: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/24.jpg)
![Page 25: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/25.jpg)
exceptions are seen betw groups 14 & 15 b/c ½ filled sublevels are a little more stable than ones not ½ full
group trends: generally more difficult to add e- to larger atoms than to smaller atoms
elements w/ very negative EA gain e- readily to form anions (ions w/ neg chrg)
![Page 26: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/26.jpg)
more difficult to add e- to an anion so 2nd EA are all positive
cation- positive ionanion- negative ion
![Page 27: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/27.jpg)
½ the diameter of an ion in a chemical compound
formation of a cation leads to a decrease in radius due to the e- cloud being drawn inward as valence e- are removed
formation of anion leads to an increase in radius as additional e- repel one another
4. Ionic radii
![Page 28: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/28.jpg)
![Page 29: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/29.jpg)
periodic trends- metals form cationsnonmetals form anions
group trends- IR increases down group Why?
as you add higher energy levels, radius of ion incr
![Page 30: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/30.jpg)
chemical compounds form b/c e- are lost, gained, or shared to bring an atom to a stable octet
![Page 31: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/31.jpg)
measure of the power of an atom in a chemical compound to attract e-
valence e- hold atoms in compound together & properties of compound are influenced by conc of neg chrg closer to one atom than another
ex: NaCl
5. Electronegativity EN
![Page 32: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/32.jpg)
![Page 33: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/33.jpg)
numerical values assigned to indicate the tendency of atom to attract e-
Fluorine – most EN element & assigned value of 4
periodic trends- gradual incr in EN from L to R across period
nonmetals tend to be more EN than metals
![Page 34: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/34.jpg)
groups 1 & 2 least EN elements
halogens are most EN elements
group trends- EN either decreases down group or remains similar
![Page 35: Chemistry Chapter 5](https://reader035.vdocuments.us/reader035/viewer/2022062519/56814f59550346895dbd07bb/html5/thumbnails/35.jpg)