Unit 2 Atomic Structure & Nuclear Chemistry Section 1 Create your own notes! Obj.1 Section 2 Obj.2 Counting Subatomic Particles
The ______is defined as the smallest particle of an element that retains the properties of that element. Subatomic Particles & Their Properties Particle Symbol Location Relative Mass Actual mass in Electrical Charge in a.m.u* grams 1 amu 1.6710-24 g +1 p+
1 amu 1.6710-24 g 0 n0
.00055 amu 9.1110-28 g -1 e-
*a.m.u : atomic mass unit 1 amu (“atomic mass unit”) = 1.67 10-24 g
**The mass of the proton and neutron are very similar** **Their mass is about 2000 times larger than the mass of the electron**
What are the 2 regions of the atom as of now?
Nucleus: small, dense center containing ______and ______. Electron Cloud: region surrounding nucleus containing electrons and is mostly ______.
Counting Subatomic Particles Atomic Number Mass Number Every atom has a different number of protons, The number of protons and neutrons in a which is represented by the atomic number. nucleus of a specific atom is called the mass The number of protons determines the identity number. of the atom Atomic Number = Number of protons 2 Options: Ex: Nitrogen’s atomic number is 7 [1] Add the number of given protons & neutrons together Mass # = protons + Calculating Electrons in a Neutral Atom (A.P.E) neutrons A neutral atom has the ______number [2] USE ONLY when no element information of protons and electrons. has been given: Round atomic mass to a whole # protons = # electrons number to get an element’s most likely most common mass number. o Nitrogen’s atomic mass = 14.01 amu o Nitrogen’s mass number is To calculate the number of neutrons, subtract ______the atomic number from the mass number Number of NEUTRONS = mass number – atomic number Calculating Neutrons (M.A.N) Nitrogen: 14 – 7 = 7 neutrons Overall Charge = protons - electrons Calculating Electrons in a Ion An ion has a charge. The number of protons is Example: NOT EQUAL to the number of electrons. -1 Can be a positively charged ion called a [1] How many electrons does Br have? ______or a negatively charged ion called an ______
[2] How many electrons does Al+3 have?
Element Information: Nuclear Symbol LABEL THE PARTS BELOW
A A Z Z X X C C
SELF CHECK What are the number of protons, neutrons & electrons in each atom?
Hyphen Notation: LABEL THE PARTS!
Copper – 65 ______p __e __ n You Try: (Be Careful: Never use the given atomic mas on the periodic table to calculate mass number unless no other information has been provided. )
Nuclear Hyphen Atomic # Mass # Charge Proton Neutron Electron Symbol Notation Magnesium-25 +2
82 126 82 Section 2 Obj.2 cont. & Obj. 4 How Do Atoms Differ: Isotopes
Isotopes are atoms of the same element that have the same number of protons but a different number of ______. Most elements contain a mixture of 2 or more isotopes. Each one having its own mass and abundance. Some isotopes are radioactive and unstable. You can identify an isotope by its different mass number of the same element
Carbon-12 Carbon-13 12 13 C C 6 6
Fill in the chart using the diagram in the presentation Atomic Isotope Protons Neutrons Electrons Mass (a.m.u) number
Lithium-6
Lithium-7
Lithium-8
You Try ?
What the number of protons, neutrons and electrons in each? 19 18 203 194 F F Hg Hg
9 9 80 80 How to calculate Average Atomic Mass?
Average atomic mass is the weighted ______of the masses of all naturally occurring isotopes. Average Atomic Mass Equation:
Average atomic mass = (% abundance of isotope x mass of 1st isotope) + (% abundance of isotope x mass of 2nd isotope) + ……… Cl-35 and Cl-37 Why is the AAM = 35.45 amu ?
Example 1: Element x has 2 natural isotopes. Calculate its average atomic mass. 1st isotope has a mass of 10.012 a.m.u. with 19.91% abundance. 80.09% of the 2nd element has a mass of 11.009 a.m.u.
Example 2: Calculate the average atomic mass of copper if it has 2 isotopes. 69.11% has a mass of 62.93 a.m.u and the rest has a mass of 64.93 a.m.u.
Section 3 Obj.3 Nuclear Decay Reactions
Nuclear chemistry is the study of the changes of the ______of atoms. Nuclear Reactions involve changes within the nucleus where as chemical reactions involve the loss, gain or sharing of electrons.
The Nucleus
Contains ______and neutrons. They are collectively called ______.
Radioactivity
A ______nucleus holds together well. An unstable nucleus will decay or break down, releasing particles and/or energy in order to become stable. An atom with an unstable nucleus is considered “______”.
Transmutation
Type of nuclear reaction that will change the number of ______and thus will create a different ______. There are several ways radioactive atoms can decay into different atoms!
Basic Types of Radioactive Decay
Particle Symbol What Happens? Example Penetrating Power Type
Atomic number decreases by (1) LOW: Can be Alpha or ____ and mass number blocked by decreases by ____ paper/clothing
(100) MEDIUM: can penetrate the skin; Atomic number increases by need to be Beta or _____ but the mass number protected by *** stays the same clothing/thin metals like aluminum **A neutron becomes a ______and a high-speed electron that is discharged from the nucleus** (100000) HIGH: No change in atomic nor need to be Gamma mass number; occurs with protected by thick other types of decay concrete or metal like lead
Writing Balanced Nuclear Equations
The sum of ______and mass number must balance on both sides of the equation. Often problems will have 1 particle missing and you will need to identify it.
You Try! 1. Beta decay of zircomium-97 5. Complete this:
2. 6.
3. Alpha decay of americium-241 7.
4.
8. 9. Making New Elements and Isotopes: Bombarding the Nucleus All the transuranium elements (elements with atomic numbers higher than Uranium) have been made by bombarding the nucleus with neutrons and other atoms in accelerators
10. 11. 12. Section 4 Obj.3 cont. 13. Half Life
Radioactive isotopes decay at a characteristic rate measured in ______. A half-life time (T1/2) is the time required for ______of the amount of radioactive atoms to decay. The time ranges from ______to millions of ______. 14. HOW TO’s 15. 1. To calculate the number of half-lives, divide the half-life (T1/2) into the total time (T). Then cut the original amount in half the number of time determined by the # of half lives (HL). 16. 17. T / T1/2 = HL 18. 2. Algebraic equation to calculate the remaining amount left over after a certain number of half-lives have passed. 19. Amount remaining = (initial amount) (.5) HL 20. 21. Examples: 1. Suppose you have 20 grams of sodium-24. Its half-life is 15 hours. How much is left over after 60 hours. 22. 23. 24. 25. 2. Uranium-238 has a half-life of 4.46 x 109 years. How long will it take for 7/8th of the sample to decay? 26. 27. 28. 29. 30. You Try! 31. 1. 1.5 grams of a 12.0 g sample are left after 114 s. What is the half-life of radium-222? 32. 33. 34. 35. 36. 2. A sample of 3x107 Radon atoms is trapped in a basement that is sealed. The half-life of Radon is 3.83 37. days. How many radon atoms are left after 31 days? 38. 39. 40. 41. 42. 43. Section 5 Extension 44. Fusion & Fission 45. 46. Nuclear Fission Large atoms ______into smaller atoms
Generates huge amounts of ______. 47. Carried out in ______ Could result in a chain reaction of fission like the
______48. 49. 50. 51. 52. 53. 54. Nuclear Fusion Smaller atoms are ______to form a larger atom. Occurs in the ______and ______ Generates huge amounts of ______55.
56.