1. And Write about ANY of the families of the ELEMENTS
HOMEWORK:
For next Monday Sept 9th
CONSTRUCT BY HAND
PERIODIC TABLE
ON CARTULINAOF 21.5 x 28 cms
And Write about ANY of the families of the ELEMENTS
Only Symbols, Atomic number and atomic weight

2. Bohr model
In atomic physics, the Bohr model, introduced by Niels Bohr in 1913, depicts the atom as small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity. After the cubic model (1902), the plum- pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement to the Rutherford model is mostly a quantum physical interpretation of it. The Bohr model has been superseded, but the quantum theory remains sound

3. 1. Subatomic Particles Particle Symbol (table O) Charge Mass (amu)
Amu: Atomic mass unit
U:1 g /60..22x10(22) mol(-1)
Avogadro=Number of atoms or molecules in one mole
1. Subatomic Particles
Particle
Symbol (table O)
Charge
Mass (amu)
Location
Within atom structure
Electrons e
0e-1
0β-1
Negative
(-1)
1/Avogardos
0 amu
Outside nucleus
( in various energy levels)
Protons p
1p1
1H1
Positive (+1)
1 amu
Nucleus
Neutrons n
1n0
Neutral
(0)

4. Special notes on subatomic particles
In a neutral atom # of protons=#of electrons.
Atoms are electrically neutral.
If the number of protons does not equal the number of electrons you have a charged atom known as an ion.
# protons > # electrons forms a + ion (cation)
# electrons > # protons forms a – ion (anion)
The charge on the nucleus is positive.
Most of the mass of an atom is in nucleus.

5. Atomic Number (z) 1913—Henry Mosley (Untroduced the concept)
Is used to identify an atom
Indicates the number of protons
In a neutral atoms also gives the number of electrons
Also called the Nuclear Charge

6. 3. Mass Number (A)
Total number of protons and neutrons in the nucleus of an atom. (nucleons)
Notation: AXZ
Mass # = #protons + # neutrons
# neutrons = Mass # - # protons
36=p+ and e
no=48

7. Exercise:
*Mass # = #protons + # neutrons * protons= Num. Electrons *# neutrons = Mass # - # protons
Sample Atom
*ATOMIC MASS
Notation
Protons (atomic #)
Neutrons (mass #- atomic #)
Electrons(s ame as atomic#)
Carbon-12
C-12
12C6 6
12-6=6
Chlorine-35 Cl-35
35Cl17 17
35-17=18
Chlorine-37
Cl-37
37Cl17
37-17=20
Neon-20 Ne- 20
20Ne10 10
20-10=10
Oxygen-16 O- 16

8. Oxygen Atom Structure

9. Determine the # of protons, neutrons, and electrons for these added examples:
19F Negatively charged
10 neutrons
10 electrons
24Mg12
12 protons
24-12=12 neutrons
12 electrons
24Mg Positively Charged
12 neutrons
10 electrons

10. Isotopes
Thomson (1912) found 2 types of neon atoms and Soddy (1910) found 2 types of uranium atoms.
2 elements that have the same atomic number but different mass numbers
Based on atomic structure: 2 elements that have the same number of protons but different number of neutrons.
For example: Cl-35 and Cl-37

11. Isotopes are not random. Isotopes are formed based on their stability
Isotopes are not random. Isotopes are formed based on their stability. The more chemically stable an isotope is the higher abundance it will have. Some isotopes are radioactive and are therefore described as radioisotopes
For example 14Carbon is a radioactive isotope of carbon whereas 13Carbon are stable isotopes therefore is in abundance over 14Carbon.

12. Carbon Atom Carbon 14 Isotope
Used for radiocarbon dating

13. 5. Atomic Mass (Different than Mass NUMBER?)
Decimal number (Explain)
Average of all the naturally occurring isotopes for a particular element
If you round the atomic mass it gives you the mass number for the most common isotope.
Unit is amu (atomic mass unit)
1 amu is 1/12 the mass of C-12
Gram atomic mass= amu but in grams

14. IF HYDROGEN ATOM STRUCTURE IS
Neutron?:

15. Try the following:
Determine the number of protons, neutrons, and electrons for the following isotopes of hydrogen: H2;H3
Solution:
Hydrogen-2 (deuterium) 2H p,1n,1e
Hydrogen-3 (tritium) 3H p,2n,1e

16. Naturally occurring chlorine consists of 75% Cl-35 and 25% Cl-37
Naturally occurring chlorine consists of 75% Cl-35 and 25% Cl-37. Find the average atomic mass.
.75(35) + .25(37)= amu or
75(35) (37) =35.50 amu
100

17. 3. Calculate the atomic mass of an element with isotope A occurring 70
3. Calculate the atomic mass of an element with isotope A occurring 70.0% of the time with a mass of 13.0 amu and isotope B occurring 30.0% of the time with a mass of 15.0 amu.
.70 (13.0) (15.0) =13.6 amu

18. An element X has three isotopes X-30 has a 50
An element X has three isotopes X-30 has a 50.0% abundance, X-28 has a 30.0% abundance and X-31 has a 20.0% abundance.
.500(30) (28) (31) = 29.6 amu

19. 5. There are two isotopes of element Z, 60
5. There are two isotopes of element Z, 60.0% of the atoms have a mass of 58.0 amu and 40.0% have a mass of 57.0 amu. Calculate theatomic mass of element Z.
.600(58.0) (57) = 57.6 amu