This document discusses atomic bonding, isotopes, and radioactivity. It explains that atoms form ionic bonds by gaining or losing electrons to achieve stable full outer shells, becoming positively or negatively charged ions. Atoms form covalent bonds by sharing electrons. Isotopes are atoms with the same number of protons but different numbers of neutrons, giving them different atomic masses but similar chemical properties. Some isotopes are radioactive as they emit radiation to become more stable nuclides. The document describes an experiment to discover properties of a new element by determining the relative abundances and masses of its three naturally occurring isotopes to calculate the average atomic mass.

1. Biochemistry Part 2 Bonding, Isotopes, and Radioactivity

2. Recap Atomic structure Valence electrons Happy  atoms are full atoms (8 ve or 2 ve) How do we make them happy??? STEALING or SHARING valence shell electrons to have a complete ring…remember the Samaras?

4. Ionic Bonds Atoms become IONS by losing or gaining electrons What is the charge of an electron? Sooo…they are losing or gaining a NEGATIVE charge Covalent Bonds SHARING of electrons Val. Electrons spend their time around both atoms involved in the bond NOT always equally shared, but still shared Two Types of Bonds

5. Ionic Compounds Ions A POSITIVELY or NEGATIVELY charged particle Formed by gaining or losing electrons in an effort to become stable Atom that lose one or more electron(s) POSITIVELY charged..CA+IONS Atom that gains one or more electron(s)ANIONS STEALING e-

6. Which atoms become ions? Which ever are veryyyyy close to being happy They either have to lose or gain one or two electrons to have a complete outer ring Remember, atoms are LAZY, they want to do as little work as possible to be happy Groups 1A and 2A will lose e- and become +1 or +2 ca+ions (+) Groups 6A and 7A greedy little suckers that will steal e- to become -1 or -2 anions (-)

9. Covalent Compounds Not greedy…they would rather share Their outer rings are about half way full… Groups 3,4 and 5 The # of bonds an atom can form is equal to the number of valence electrons it NEEDS to be happy Oxygen has___v.e….it needs___to be happy, so it can make ____ bonds.

10. Covalent Bonds make… 2 or More atoms covalently bonded make a compound called a MOLECULE Sharing of 2 e- b/t 2 atoms single bond (pretty strong) Sharing of 4 e- b/t 2 atoms double bond (stronger hold) Sharing of 6 e- b/t 2 atoms triple bond (really strong!)

12. 7 Diatomic Molecules Di- means.. 2 Atomic means Referring to atoms Molecules Covalently bonded atoms Put it together and what do you get: 2 atoms of the same element that are covalently bonded to EACHOTHER Occurs naturally in Nature Br2 I2 N2 Cl2 H2 O2 F2 BrINClHOF!!!

13. Recap… When we change # of protons we get… A different element We don’t want to change this! When we change # of electrons we get… IONS! Cations + LOSE an electron Anions – Gain an electron When we change the # of neutrons we get…

14. ISOTOPES! Atoms with the same atomic number but with different atomic masses are called isotopes Changing the # of neutrons in an atom will affect the… MASS NUMBER= protons + neutrons Isotopes of an element have the same # of p+ and e-…so they behave the same CHEMICALLY The average of all the mass #s of the isotopes of an element give us that decimal on the periodic table (Average Atomic Mass)

17. Radioactive Isotopes As the difference b/t p+ and n. in the nucleus increases, the nucleus becomes more unstable When p=n , nucleus is stable… When n>p, nucleus is unstable Nucleus will give off tiny amounts of energy to become stable (protons or neutrons) Radiation=energy Radioactive=when something gives off energy

18. Isotopes of the Element Potassium with a Known Natural Abundance Mass # Natural Abundance Half-life 39 93.2581% Stable 40 0.0117% 1.265×10+9 years 41 6.7302% Stable

19. Isotopes continued Radiation can be dangerous in large amounts but in small amounts it can be useful in science Geology-determine age of fossils and rocks Medicine-treat cancer and detect cell processes (tracers) PET scans, CT scans, MRI Commercial-kill bacteria that spoils certain foods

20. Mm Isotope Discovery Lab

21. New Discovery!!! You and your research team have discovered a new element…Mm… Mm is an essential element in the human diet There are three naturally occurring isotopes of the element Mm Atomic Number of Mm is 30 Your teams goal is to determine the average atomic mass of the element Mm by determining the percent abundance of each naturally occurring Mm isotope You have already determined the masses of each of the three different Mm isotopes:

22. Calculations Percent Abundance of isotope Mm-R= (Total # of Mm-R in nature/ Total # of all Mm-isotopes in nature) x 100% Percent Abundance of isotope Mm-B= (Total # of Mm-B in nature/ Total # of all Mm-isotopes in nature) x 100% Percent Abundance of isotope Mm-Y= (Total # of Mm-Y in nature/ Total # of all Mm-isotopes in nature) x 100% Mass Contribution of each isotope: (amu of Mm isotope) x (percent abundance of Mm isotope in nature) Average Atomic Mass= [(mass contribution of Mm-R) + (mass contr. of Mm-B) + (mass contr. of Mm-Y)] Show ALL Calculations Take Pictures of Set up Record all procedures

23. Homework Complete Lab Report For Isotope Lab See lab report guidelines Extra Credit: Make A Creative Periodic Table Element Box for your New Element….Be sure to include all your information you gathered from your extensive research! Atomic Number Average Atomic Mass Chemical Symbol BE CREATIVE!