1. Nuclear Chemistry Vodcast 4 Unit 2 – Atomic & Molecular Structure

2. Nuclear Radiation ______ Antoine Henri Becquerel along with Marie and Pierre Curie discovered that _________ emits _______ rays. Marie Curie named the process of uranium giving off rays, ____________. __________ is the penetrating ____ given off a radioactive source. invisible rays 1896 uranium radioactivity Radiation

3. Nuclear Radiation Becquerel and the Curies won the Nobel Prize in _______ in _____ for their discovery This theory disproved _______ idea of an _________ atom. physics 1903 Dalton’s indivisible

4. Certain isotopes, called ___________ are radioactive because they have _______ nuclei. _______ of a nucleus is determined by the ratio of _______ to ______. Too many _________ leads to an _______ nucleus. Nuclear Radiation unstable radioisotopes Stability neutrons protons neutrons unstable

5. Nuclear Radiation When a nucleus is unstable, it _____ energy by emitting radiation during the process called __________ _______. Through radioactive _______, unstable _______ of one element are changed into stable, ___________ isotopes of a _______ element. This process is called ____________. loses nonradioactive radioactive decay isotopes different transmutation

6. Nuclear Radiation “Trans-” means across and “mutation” is a change. Radioactive decay is __________ and does not require any input of ______. energy spontaneous

7. Types of Radiation There are _____ main types of radiation that can be emitted during _________ _____. _______ radiation  _______ radiation  _______ radiation  alpha beta gamma three radioactivedecay

8. Types of Radiation Alpha radiation consists of _______ nuclei that have been emitted. Alpha particles contain ____ protons and _____ neutrons and have ____ charge. An alpha particle is written as  or ____. The charge is ___ used. helium two 2+ 4242 He not

9. Types of Radiation When an atom _______ an alpha particle, the atomic number of the product atom is ______ by _______ and its _____ number is lower by _____. Uranium-238 thorium-234 +  particle U 238 92 Th 234 90 He 4 2 + loses two four lower mass

10. Types of Radiation Since  -particles have a large _____ and charge, they do not travel far and can be stopped by _______ and even _____________. We can say alpha particles are _____________. They can be _________ if they are swallowed. paper hazardous mass dead skin cells low-penetrating

11. Types of Radiation _____radiation consists of ___________________formed by the decomposition of a ________ in an atom. The neutron breaks into a ______ and an _________. The fast-moving ________ are called ___________ neutron electrons beta particles Beta fast-moving electrons proton electrons

12. The _______ stays in the nucleus and the electron is _______ from the atom. Beta-particles are represented by _ and using Carbon-14nitrogen-14 +  -particle radioactivestable Types of Radiation N 14 7 e 0 C 14 6 + protons ejected  0 e

13. Types of Radiation Beta-particles have ___ the charge and are much _____ than alpha- particles. Therefore they can travel _______ and are ____ penetrating. Beta-particles can be stopped by ____________ and pieces of _____. lighter further wood half more aluminum foil

14. Types of Radiation Gamma radiation is also called _____________ radiation. The _____ we see is also electromagnetic radiation, but much _____ energy. Gamma rays are often emitted by nuclei of ___________ radioactive atoms along with _______ or_______ radiation. light alpha electromagnetic lower disintegrating beta

15. Types of Radiation Gamma rays have no ______ and no _______ charge. They are represented with _______ symbol . Gamma radiation does not change the _______ number or _______ number of an atom. electrical mass Greek atomic mass

16. Types of Radiation X-radiation (_____) are ___ emitted during radioactive decay. X-rays are made as excited ________ in certain _______ _____ their energy. Except for their origins, gamma rays and x-rays are very ______. metals x-raysnot electronslose similar

17. Types of Radiation They both pass through ______, _______, and the __________. They can be stopped by several _______ of _______or several centimeters of _____. wood meters paper human body concrete lead

19. Review Alpha radiation is emitted when thorium-235 decays. Write a balanced nuclear reaction for its decay. Ra 231 88 He 4 2 Th 235 90 +

20. Review Beta radiation is emitted when strontium-90 decays. Write a balanced nuclear reaction for its decay. Y 90 39 e 0 Sr 90 38 +

21. Electron Capture Sometimes electrons can be captured. Nickel- 59 will capture an electron: Co 59 27 e 0 Ni 59 28 +

22. Nuclear Fission & Fusion With spontaneous nuclear fission a heavy nucleus ______ into lighter, smaller nuclei and releases large amounts of _________ Californium-252 can split spontaneously Ba 142 56 Cf 252 98 + Mo 106 42 + n 1 0 4 + energy splits energy

23. Einstein and Nuclear Reactions A tiny amount of mass will convert to an enormous amount of energy!

24. Nuclear Fission & Fusion Fusion occurs when nuclei _______ to produce a nucleus of _______ mass. Fusion reactions tend to release _______ energy than _______ reactions. combine more greater fission

25. Nuclear Fission & Fusion Fusion reactions occur in the Sun. ________ nuclei fuse to make _______ nuclei. Below is the fusion reaction that occurs on the Sun: 4 1 H + 2 0 e  4 He + energy 1 -1 2 Hydrogen helium

27. Positron Emission A positron has a mass identical to an electron, but its charge is +1 instead of -1 Sodium-22 is a positron emitter and is used in medicine to diagnose small lesions in the brain. What does sodium- 22 decay to? Ne 22 10 e 0 +1 Na 22 11 +

28. Uranium-235 is hit with a neutron and becomes Uranium 236, which is very unstable. This then decays into Krypton-91 and what other element? Nuclear Fission & Fusion 235 U + 1 n  236 U  91 Kr + ____ 92 0 92 36 235 U + 1 n  236 U  91 Kr + 145 Ba 92 0 92 36 56