Day 8 Isotope Quiz Chapter 24 Section 1 Band of Stability Work Sheet

Daily Reaction Na(OH) + CuCl2  NaCl + Cu(OH)2 Questions: The periodic table is also arranged by increasing atomic number or the number of protons in the nucleus. It is the number on top of each symbol. Elements can be combined to form single units such as (OH). OH is call hydroxide and is an important component of a “base”. A base is opposite of an acid and can still be very dangerous. Questions: What type of reaction is this? Using your periodic table identify the symbols and names. What row is each element in. Identify the atomic number.

Chapter 24 - Nuclear Chemistry Characteristics of Chemical and Nuclear Reactions Chemical Reactions Nuclear Reactions Occur when bonds are broken and formed. Occur when nuclei emit particles and/or rays. Atoms remain unchanged, though they may be rearranged. Atoms are often converted into atoms of another element. May involve protons, neutrons, and electrons Involve only valence electrons. Associated with small energy changes. Associated with large energy changes. Reaction rate is influenced by temperature, pressure, concentration, and catalysts. Reaction rate is not normally affected by temperature, pressure or catalyst.

Radioisotopes Isotopes of atoms with unstable nuclei Name the 3types of radiation that you know Alpha Beta Gamma

Properties of Alpha, Beta and Gamma Radiations The Differences Properties of Alpha, Beta and Gamma Radiations Property Alpha(α) Beta (β) Gamma (γ) Composition Alpha particles Beta Particles High-energy electromagnetic radiations Description of radiation Helium nuclei Electrons photons Charge 2+ 1- Mass 6.64 x 10 -24 9.11 x 10 -28 Approximate Energy 5 MeV 0.05 to 1 MeV 1 MeV Relative penetrating Power Blocked by Paper Blocked by metal foil Not completely blocked by lead or concrete

The Equations Alpha Radiation Beta Radiation Gama Radiation

2 More types of radiations Positron Emission A proton is converted into a neutron and a positron. A positron is a positively charged electron. Electron Capture An electron and proton combine to form a neutron

Nuclear Stability Why are atoms unstable? Proton to neutron ratio What are Nucleons Positively charges protons Neutral neutrons

Half Lives – Radioactive Decay Half Life – time required for half of the nuclei to decay into its products. 3 Steps Determine the number of half lives by Multiply the the amount you started with by the number of (½) lives. That will tell you how much is left.

Half Life Example... Formula Strontium – 90 has a half life of 29 years. In 58 years how much strontium – 90 will be left if you started with 20 g? Follow your steps Determine how many Half lives. 58/29 = 2 Multiple the number of half lives by what you started with. 20g (½ ) (½) = 5g remaining Formula N = No (½ )... N = How much remains No = How much I started with (Orignal amount) (½ ) = the half lives

The Band of Stability All elements with atomic numbers greater than 83 are radioactive! Isotopes with a ratio of neutrons to protons above 1.5 are unstable and undergo radioactive decay. Band of Stability Worksheet for homework

Look Ahead… Homework Problems: Day 9 - Chapter 24 Section 2 Day 10 – Quiz: Radioactive Decay