RADT 1085 Chapter 2
An electron emitted from the nucleus during some kinds of radioactive decay is known as:
beta particle
Figure 2-1 shows the following approximate sizes: an atom is 10^-10 and Earth is 10^7. By how many orders of magnitude do these objects differ
17
90/38 Sr has a half life of 29 years. If 10 MBq were present in 1950, how much would remain in 2010?
2.5 MBq
If atoms large enough to have electrons in the T shell existed, what would be the maximum number allowed in that shell if V is the most outer shell?
200 electrons
How much more tightly bound are K-shell electrons in tungsten than L- shell, M-shell, and free electrons
58 keV 67.2 keV 70 keV
No outer shell can contain more than _____ electrons.
8
Using the data in Table 2-1, determine the mass of 99Tc in atomic mass units and in kilograms
99 amu, 1.64 x 10^-25
The arrangement of the periodic table of elements
An arrangement of all known elements into rows and columns
Describe how ion pairs are formed.
An ion pair is formed when an electron is removed from an atom by ionizing radiation.
Why doesn't an electron spontaneously fly away from the nucleus of an atom
Electrostatic force of attraction, electron binding energy
Radioactive decay results in
Emission of alpha particles, beta particles, and gamma rays
The time required for a quantity of radioactivity to be reduced to one half its original value
Half life of a radioisotope
K shell
Innermost electron shell
What is the removal of an orbital electron from an atom
Ionization
What has the same atomic number and same atomic mass number
Isomer
Atoms that have the same number of neutrons but different number of protons are
Isotones
Diagram the expected electron configurations of Ca
K-2 L-8 M-8 N-2
Describe the difference between alpha and beta emission
Mass and charge on particle
Alpha particle
the nucleus of a helium atom, consisting of two protons and two neutrons, which is emitted during alpha decay
Photon
Any quantum of electromagnetic radiation, no mass and no charge
The force that keeps an electron in orbit is called what?
Centripetal force
Any quantity of one type of molecules
Chemical compound
Into how many groups are all elements arranged
Eight
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
The spontaneous emission of particles and energy in order to become stable
Radioactivity
What determines the chemical properties of an element
The arrangement of electrons in outermost shell
What is essentially empty space
The atom
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).
Rutherford atom
The first description of an atom having a nucleus
radioactive half-life
Time required to reduce radioactivity to half its original value
W is the chemical symbol for
Tungsten
chemical compound
a new substance that forms when atoms of two or more elements react with one another
A helium nucleus with two protons and two neutrons is called a(n) ____.
alpha particle
What is the smallest particle that has all the properties of an element
atom
The smallest particle of an element is
atoms
Where do x-rays come from?
electron cloud
List the fundamental particles within an atom.
electrons, protons, neutrons
Atomic nuclei that have the same atomic mass number but different atomic numbers are
isobars
Atoms that have the same atomic number but different atomic mass numbers are
isotopes
The smallest particle of a compound is
molecule
atoms of various elements may combine to form structures called
molecules
In their normal state, atoms are electrically...
neutral
The atomic mass number and the precise mass of an atom are
not equal
Where do gamma rays come from?
nucleus
For what is Mendeleev remembered?
periodic table of elements
Positron
positively charged beta particle
What are the fundamental particles of an atom
proton, electron, neutron
Nucleons
protons and neutrons
