1. Chemistry Midterm Review

2. Explain the difference between fission and fusion
Fission is splitting of a big nucleus into 2 smaller ones
Fusion is combining 2 nuclei to make one bigger one

3. Write a balanced decay equation for the decay of Pb-210
Beta decay forming Bi-210

4. A sample of I-131 decays to 1 g in 40 days
A sample of I-131 decays to 1 g in 40 days. What was the mass of the original sample?
1g 2g 4g 8g 16g 32g
time 0

5. Write the symbol, mass and charge for the alpha, beta and gamma particles
Alpha mass = 4, charge = 2
Beta mass = 0, charge = -1
Gamma mass = 0 charge = 0

6. Nuclear reactions release large amounts of energy. Why?
Mass is converted to energy

7. Name the 5 types of reactions
Synthesis
Decomposition
Single replacement
Double replacement
combustion

8. Complete and balance the following reaction: sodium chloride and barium
2 NaCl + Ba Na + BaCl2

9. What 2 products always form in a combustion reaction?
Carbon dioxide
water

10. Balance and Identify the type of reaction: Chromium and oxygen yields chromium (III) oxide
4Cr + 3 O Cr2O3
synthesis

11. If it has mass and takes up space it is called….
matter

12. How many e- pairs in and F orbital?7

13. Draw Lewis Dot structure of N and C

14. What element is represented by [Ne] 3s2 3p4

15. How many neutrons are in Se-79?45

16. What were 2 conclusions from Rutherford’s Gold Foil Experiment?
Atoms have small dense + charged nucleus
Atoms are mostly empty space

17. Draw orbital notation for e- in oxygen atom
1s2 2s2 2p4

18. How many valence e- are in gold and what orbitals are they in?
6s1 or 6s2

19. The first element to contain a pair of e- in a d orbital is:Ti

20. Isotopes of B are B-11 (80. 2%) and B-10 (19. 8 %)
Isotopes of B are B-11 (80.2%) and B-10 (19.8 %). Show set up for calculating ave atomic mass
(11 x 80.2) + (10 x 19.8)
______________________
100

21. Which atom has the smallest radius: Cs, Fr, Ba, Ra, and explain why
Ba, because Ba has more protons than Cs, pulling e- closer and making it smaller
Ba also has less energy levels than Ra

22. What is the definition of atomic radius?
One-half the distance between the nuclei of 2 adjacent atoms

23. Name the 3 types of elements on the periodic table
Metals, non metals, and metalloids

24. List 3 properties of metals
Malleable,
ductile,
Conductors
luster

25. List 2 properties of non metals
Brittle
Poor conductors
No luster

26. Which group contains elements in all 3 phases of matter at room temperature?17

27. The elements in the modern Periodic Table are arranged according to:
Atomic number

28. Describe the ionization energy of metals:
low

29. What happens to atomic radius from left to right across a period? Why?
Radius gets smaller because more protons pull electron closer in

30. Which element has an ionic radius that is larger than its atomic radius? K, Zn, Cl, Cr

31. Define electronegativity
An element’s ability to attract e- in a compound

32. Which element has the largest atomic radius: Li, O, C, F, N? Why?
Li, because the others have more protons pulling e- in closer

33. What is the trend in ionization energy as you go across period 3? Why?
Increases, because more protons pulling on e-

34. What is the trend in ionization energy as you go down group 16? Why?
Decreases, because of shielding, e- farther from nucleus and easier to remove

35. What intermolecular force acts on molecules of hydrogen gas?
Van Der Waals

36. Which bond has the greatest ionic character: Al-F, C-O, K-Br, C-N?

37. Use poetic language to describe the metallic bond
Positive ions immersed in a sea of mobile electrons

38. Give an example of a polar covalent bond
H-Cl

39. Ionic bonds form between what two types of elements?
Metal and non metals

40. What are the 7 diatomic elements
H, O, N, F, Cl, Br, I

41. When does hydrogen bonding occur?
+ N, O or F

42. Draw a Lewis Dot structure of calcium fluoride

43. Draw a Lewis dot structure of the ammonium ion

44. What kind of bond will form between H and N?
Polar covalent

45. Write formula for Cobalt (III) fluoride
CoF3