Ch. 3 - Challenge Q's
Fig. 3.1 shows the following approximate it an atom, 10-10 m; the Earth, 107 m. By how m orders of magnitude do these obiects differ?
17 orders of magnitude.
If atoms large enough to have electrons in the T shell existed, what would be the maximum number allowed in that shell?
200
alpha
4 amu MeV +2 Nucleus
Using the data in Table 3.1, determine the mass of 99Tc in atomic mass units and in kilograms.
99 amu; 1.64 10^−25 kg.
The arrangement of the periodic table of elements
An arrangement of all known elements into rows and columns. The rows relate to the number of electron shells present; the columns relate to the number of electrons in the outermost shell.
Describe how ion pairs are formed.
An ion pair is formed when an electron is removed from an atom by ionizing radiation.
List the fundamental particles within an atom.
Electrons, protons, and neutrons.
Why does an electron not spontaneously fly away from the nucleus of an atom?
Electrostatic force of attraction, electron binding energy.
How does carbon-14 dating determine the age of petrified wood?
Fixed 14C in petrified wood decays, while 14C in living wood is replenished.
K shell
Innermost electron shell.
Diagram the expected electron configuration of 40Ca.
K = 2, L = 8, M = 8, N = 2.
Describe the difference between alpha and beta emission.
Mass and charge on the particle. An alpha particle has four units of mass and two units of positive charge. A beta particle has essentially no mass and one unit of negative charge.
gamma
0 MeV 0 Nucleus
X-rays
0 keV 0 Electron shells
beta +
0 amu keV +1 Nucleus
beta -
0 amu keV −1 Nucleus
Photon
Any quantum of electromagnetic radiation. It has no mass and no charge
90/38Sr has a radioactive half-life of 29 years. If 10 MBq were present in 1960, approximately how much would remain in 2020?
Approximately 2.5 MBq.
Nucleons
Neutrons and protons.
Chemical compound
New substance that is formed when two or more atoms of different elements combine.
Who developed the concept of the atom as a miniature solar system?
Niels Bohr.
Can atoms be ionized by changing the number of positive charges?
No. Positive charges (protons) do not move, they are confined to the nucleus.
How many protons, neutrons, electrons, and nucleons are found in the following? 17/8 O 27/13 Al 60/27 Co 226/88 Ra
O: 8, 9, 8, 17; Al: 13, 14, 13, 27 Co: 27, 33, 27, 60 Ra: 88, 138, 88, 226.
For what is Mendeleev remembered?
Periodic table of the elements.
What determines the chemical properties of an ele-ment?
The arrangements of electrons in the outermost shells.
What property of an atom does binding energy describe?
The energy required to hold nucleons together as a nucleus (nuclear binding energy). The energy required to maintain electrons in orbit about the nucleus (electron binding energy).
The Rutherford atom
The first description of an atom having a nucleus.
Alpha particle
The nucleus of the helium atom—two neutrons and two protons.
Radioactive half-life
Time required to reduce radioactivity to half its original value.
W (chemical symbol for what element?)
Tungsten.
How much more tightly bound are K-shell electrons in tungsten than (a) L-shell electrons (b) M-shell electrons (c) free electrons? (Refer to Fig. 3.9.)
a. 58 keV. b. 67.2 keV. c. 70 keV.
Positron
positively charged beta particle.
