1. Semester I Review ANSWERS

2. Semester I Review How many sig-figs are found in each number?  0.3453  30054  3001  3.0024  0.000232

3. Semester I Review Round each number to three sig-figs.  4567845700  0.0028940.00289  23.7623.8  100.5100.  56.79956.8

4. Semester I Review Which of the following is a mixture.  Pure watercompound  Clean airhomogenous mixture  Iron (II) oxide compound  Salt waterhomogenous mixture  Carbon dioxide compound

5. Semester I Review Which of the following is a chemical change.  Cutting paperphysical  Boiling waterphysical  Rusting ironchemical  Burning gasolinechemical

6. SymbolMass #Atomic #ProtonsNeutronsElectrons X - _25__ 25 10 15 10 Y - 35 3514 21 14 Z - _56__56 25 3125 Complete the table using the given numbers

7. Semester I Review Calculate the average atomic mass given the following data: element Y has three isotopes 35.0% = 23.5 amu, 55.0% = 25.0 amu and 10.0% = 26.0 amu. (35x23.5) + (55x25.0) + (10x26.0) = 24.6 100

8. Semester I Review 25.0 grams of a given metal displaces 44.2 mL of water; what is the density of the metal? 25.0g/44.2mL = 0.566g/mL

9. Semester I Review What did each scientist contribute to the development of the modern atom.  Dalton = proof of the atom  Thomson = cathode rays are electrons  Rutherford = dense positive nucleus, electrons outside nucleus, atom mostly empty space  Milliken = mass to charge ratio of the electron

10. Trial #MeasurementTrue Value = 34.50 134.56 Accurate and precise 234.45 334.78 Determine if the data below is accurate, precise, both, or neither Calculate the percent error using the average of the measurements. (34.60 – 34.50) x100 = 0.2899% 34.50

11. Semester I Review 1. The splitting of a nucleus is known as ___fission _____. 2. The combining of two small nuclei to form a larger one is known as ____Fusion______. 3. Give the formula of an alpha particle and beta particle.

12. Semester I Review 1. Decay of polonium-218 by alpha (  ) emission. 1.  + 2. Decay of carbon – 14 by beta emission 3.  + 4. Decay of Thorium - 232 by an electron capture 5. + 

13. Semester I Review 1.The half-life of phosphorous-30 is 2.5 min. If you start with 55 g of phosphorus-30, how many grams would remain after 27.5 min? Mfinal = (55g)(.5) 11 = 0.027g

14. Semester I Review A radioactive isotope decayed from 200.0 grams to 3.125 grams in 15 years. Determine the half-life of the isotope. 3.125g = 200.0(0.5) X 64 = 2 X X = 6, so 6 half-lives have passed in 15 years. Therefore each half-life is 2.5 years long

15. Semester I Review Calculate the wavelength of electromagnetic radiation with a frequency of 6.5x10 16 Hz. 4.6x10 -9 m Calculate the energy of the above electromagnetic radiation. 4.3x10 -17 J

16. Semester I Review If n=4; how many sublevels 4, Orbitals 16, and Electrons are present 32? T or F (p) sublevels have 7 orbitals T or F (d) sublevels hold only 6 electrons T or F (s) sublevels hold 2 electrons

17. Semester I Review For the element Cobalt; give the: Long hand electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 7 Box and arrow notation Noble gas configuration [Ar] 4s 2 3d 7 Electron Dot Structure

18. Semester II Review Which of the following elements has the smallest first ionization energy: potassium or calcium? Which of the following has the smallest atomic radius: O or S? The energy required to remove an electron from a gaseous atom is called the Ionization energy.

19. Semester II Review Atomic size generally decreases as you move left to right in a period. How does atomic radius change down a group in the periodic table?Increases How does ionization energy change as you move up and to right on the periodic table? Decreases up and increases to the right

20. Semester II Review Sheilding will increase as you go down a group. Sheilding will remain constant as you move left to right across a period. Electronegativity will decrease as you move down and to the left. Columns on the periodic table are known as groups or families. Rows on the table are known as periods.