Semester I Review

1
Semester I Review

• ANSWERS

2
Semester I Review

• How many sig-figs are found in each number?
• 0.345 3
• 3005 4
• 300 1
• 3.002 4
• 0.00023 2

3
Semester I Review

• Round each number to three sig-figs.
• 45678 45700
• 0.002894 0.00289
• 23.76 23.8
• 100.5 100.
• 56.799 56.8

4
Semester I Review

• Which of the following is a mixture.
• Pure water compound
• Clean air homogenous mixture
• Iron (II) oxide compound
• Salt water homogenous mixture
• Carbon dioxide compound

5
Semester I Review

• Which of the following is a chemical change.
• Cutting paper physical
• Boiling water physical
• Rusting iron chemical
• Burning gasoline chemical

6
Complete the table using the given numbers
Symbol Mass Atomic Protons Neutrons Electrons
X - _25__ 25 10 10 15 10
Y - 35 35 14 14 21 14
Z - _56__ 56 25 25 31 25
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
Determine if the data below is accurate, precise,
both, or neither
Trial Measurement True Value 34.50
1 34.56 Accurate and precise
2 34.45 Accurate and precise
3 34.78 Accurate and precise
Calculate the percent error using the average of
the measurements.
(34.60 34.50) x100 0.2899 34.50
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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.
2. ?
3. Decay of carbon 14 by beta emission
4. ?
5. Decay of Thorium - 232 by an electron capture
6. ?

13
Semester I Review

• 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 2X
• 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 6.5x1016 Hz.
• 4.6x10-9 m
• Calculate the energy of the above electromagnetic
  radiation.
• 4.3x10-17 J

16
Semester I Review

• If n4 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
• 1s2 2s2 2p6 3s2 3p6 4s2 3d7
• Box and arrow notation
• Noble gas configuration
• Ar 4s2 3d7
• 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.