1. Atomic Structure & Periodic Table Introduction
Physical Science
JPHancock

2. The Atom Basic building block of all matter
Elements on periodic table are represented as one neutral atom
Chemical symbols are abbreviated ways of representing elements
C, H, N, O
Na, Cl, Ne, Cu
NaCl, H2O, CO2

3. Parts of the Atom Protons= (+) charge Neutrons= (0) charge
Electrons= (-) charge
Quarks= smallest particles arranged in
groups of threes to make p+, e-, or n0

4. History of the Atomic Model
Aristotle 350BC
Matter made up of earth, air, fire, and water
Democritus 400 BC
Matter cannot be divided indefinately.
“atomos = uncuttable”
Dalton 1803
“Billard Ball Model” Atom solid and undivisible

5. “Plum Pudding Model” – a (+)sphere with (-) particles embedded
Thomson 1904
“Plum Pudding Model” – a (+)sphere with (-) particles embedded
Rutherford 1911
Most of the mass in a (+) nucleus surrounded by (-) electrons
Bohr 1913
(+) protons & neutral neutrons in nucleus
e- are in shells and can jump to higher levels with energy

6. Rutherford Experiment

7. Electron Cloud Model-1926 “Probability Cloud”
Electrons orbit the nucleus in energy levels or orbits.
Why is it considered a “probability cloud”?

8. EVOLUTION OF ATOM

9. PERIODIC TABLE

10. The number of neutrons = mass number –atomic number
In a neutral atom the number of e- and number of p+ are equal
Every atom of the same element has the same number of protons
MASS NUMBER =ATOMIC MASS

11. ISOTOPES
Atoms of the same element with different numbers of neutrons

13. Atomic Mass Units
Do we now know how much atoms really weigh, in pounds or grams?
Yes, but we don't normally use those units for measuring the mass of an atom. It's much more convenient to use something called the atomic mass unit, or amu.

14. Using AMU is simplier!
One gram is about 600,000,000,000,000,000,000,000 amu (that's 600 sextillion, or a 6 followed by 23 zeros). A pound is just shy of 300 septillion amu--that is, 300,000,000,000,000,000,000,000,000. (26 zeros there.)

15. Periodic Table
1869 Dmitri Mendeleev arranged the elements in order of their increasing atomic masses
He discovered a pattern and was able to give rise to the modern
periodic table

16. Mendeleev’s Periodic Table

17. PERIODIC LAW
The properties of elements are a periodic function of their atomic number
The properties change in a repeated pattern as we move across or down the periodic table
Elements are arranged by changes in physical and chemical properties

18. MODERN PERIODIC TABLE 1913 Henry G.J. Moseley
Arranged the periodic table based on increasing atomic numbers
PERIODS or Series –horizontal rows 1-7
GROUPS or Families-vertical columns
1-18 with similar properties

19. Properties of Groups
Elements of same group have same # valence electrons
Valence electrons- are the e- in the outermost energy level
Important role in chemical reactivity
Electrons closer to the nucleus have lower energy than those farther away

20. Properties of Series Horizontal rows Periods or Series
Adjacent elements in each horizontal row(period)differ in both chemical and physical properties but the properties change in a regular way across each period

21. Ionization Energy
Amount of energy needed to remove the outer electrons
As you move right to left the radius of the nucleus increases meaning the size(distance) between the nucleus and electrons is greater
As you move left to right the radius decreases meaning the electrons are valence electrons closer to the nucleus, held tighter and require more energy to remove

23. Atomic Radii

25. Electron Dot Diagrams
Used to represent valence electrons in bonding