The Discovery of Atoms

STUDY
PLAY
Who was the first to propose the idea of atoms?
Democritus
The ideas of Democritus were based on inductive reasoning.
True
The word "atom" means:
that which cannot be cut
Who is considered the father of atomic theory?
Dalton
Explain the concept: Law of Multiple Proportions.
The concept of Law of Multiple Proportions is that all matter is made up of invisible atoms, atoms are alike in everything other than their mass, they preserve their identity and are not destroyed in chemical reactions, and only whole atoms may combine.
If the following elements were to combine with each other, choose which demonstrate the Law of Multiple Proportion. Select all that apply.
Z:X = 7:1
Y:X = 11:1
John Dalton used inductive reasoning to develop his theories.
True
The first attempt at publishing a list of relative atomic masses was made by ______________.
Dalton
Select all the discoveries that J. J. Thomson is credited with making.
subatomic particles
isotopes
electrons
A device made by J. J. Thomson to process and detect electrons is the:
cathode-ray tube
Describe Thomson's concept of the atom.
Thomson's concept of the atom was referred to as the plum pudding model because it was randomly distributed electrons throughout an atom.
Prior to Thomson's discovery, the atom was thought to be indivisible. Explain the significance of Thomson's concept of the electron.
The significance of Thomson's discovery was that because he thought the atoms were positively charged with sprinkles spacing throughout it kind of like plums sprinkled through pudding which since he saw that it helped him find streams of positively charged ions.
Pitchblende is an ore of plutonium.
False
The discoverer of X-rays was ____________.
The discoverer of radioactivity was _____________.
Roentgen
Becquerel
The two elements isolated by the Curies were radium and uranium.
False
Marie Curie named polonium in honor of Poland.
True
Select all the discoveries for which Ernest Rutherford is credited.
the emissions of radioactive elements
the proton
An alpha particle is:
nucleus of helium
A beta particle:
is an electron
is emitted from the nucleus
has a -1 charge
A gamma ray is a very high speed particle with no charge.
False
Rutherford's research was primarily involved with:
defining the components of nuclei
What is a "curie"?
unit of radioactive disintegration
Rutherford and Soddy's research involved:
the theory that uranium successively disintegrated to lead
The discoveries of Niels Bohr were:
orbits of electrons
quantum energy emissions
relationship between outer shell and chemical properties
When do electrons emit energy?
when moving to a lower orbit
A quantum is a unit of:
energy
Which scientist supplied the equations to combine wave and particle theory?
Schrödinger
The mathematics of combining quantum theory with wave motion of atomic particles is known as ___________.
Wave Mechanics
James Chadwick's primary discovery was the __________.
Neutron
Two isotopes of the same element will always have the same number of ____________.
Protons
How many protons are there in the following atom?
235/92 U
92
How many neutrons are there in the following atom?
235/92 U
143
emitted from a cathode ray tube
electrons
discovered the neutron
Chadwick
discovered the electron
J.J. Thomson
postulated the quantum atom
Bohr
discovered the proton
Rutherford
father of atomic theory
Dalton
location of most of the mass of the atom
Nucleus
The man responsible for discovering that the atom is mostly space is:
Rutherford
A false statement concerning matter is:
Matter cannot be subdivided.
The true statement concerning the atomic nucleus is:
It contains most of the mass of the atom.
Which statement is true?
Isotopes of a given element have very similar chemical properties.
The atomic number of an atom is equivalent to the number of:
Protons
Rutherford coined the term used for the simplest positive charged particle and called it the:
Protons
Rutherford and Soddy's theory was:
uranium successively disintegrated to lead
Most of the mass of an atom is made up of:
the protons and neutrons
Movement of electrons about a central nucleus is a concept by:
Bohr
expressed particles by wave equation
Schrödinger
research on radioactivity
Curie
"open spaces" model
Rutherford
applied quantum theory to atoms
Bohr
shell model of atom
Bohr
Properties of elements can be predicted from their placement on the periodic table.
True
The Periodic Law states that the physical and chemical properties of the elements are periodic within the sequence of their atomic numbers.
True
A horizontal row of elements in the periodic table is known as a _____________.
Period
A vertical column within the periodic table represents a family or _________________.
Group
How many electrons can the 5th shell hold?
50
Which is the first element in the periodic table to have an electron configuration in the 4th energy level?
potassium
The element gold occurs in which period?
6th
The last element in any period always has:
eight electrons in the outermost energy level
the properties of a noble gas
Why do the chemical properties cycle through each period?
The outermost shell of all atoms with two or more electron shells will not have more than 8 electrons.
How many electrons will a non-metal generally have in its outer shell?
4 - 7
Chlorine has 17 valence electrons.
False
Which of the following elements is a transition metal?
nickel
What is a common characteristic of the transitions elements?
The next to outermost electron shell begins to fill up.
Which element is NOT in the cobalt subgroup?
Iron
Which statements are correct about a Group?
The elements in each group have similar chemical properties.
Each member of the group has the identical electron configuration in the outer shell.
Which element in Group IIA will have the highest melting temperature?
Be
Which elements are included in Group 5A?
N, P, Bi
In the vertical columns of the periodic table:
Atomic weight increases from top to bottom.
The number of shells increases from top to bottom.
The atomic number of the element which does not usually form compounds because its outermost shell is full is:
18
Which atomic number corresponds to the element which is most stable?
36
The number of positive charges in the nucleus of an atom is equal to:
its atomic number
Periodicity is best defined as:
the repeating nature of physical and chemical properties with increasing atomic number
Each period of the periodic table ends with:
Group VIIIA elements
Which element in Period 4 is the most chemically active non-metal?
Br
How many electrons will a metal generally have in its outer energy level?
1-2
An atom is most stable when it has eight electrons in its outermost energy level.
This is a statement of the _______________ rule.
Octet
What is the maximum number of electrons found in any shell of the known elements?
32
In the vertical columns of the periodic table, as the atomic numbers increase:
The numbers of electron shells increase.
The broad bands or regions located around the nucleus where the electrons are found are called energy rings.
False
Research has shown that the electrons orbit the nucleus in circular motions exactly as shown on the classic Bohr model.
False
Which statement applies to the energy change illustrated in the quantized energy emission diagram?
energy added = energy released
The light reflected off an element produces unique identifying spectrum.
False
The light emitted by an incandescent element produces:
a line emission spectrum
What causes the lines in the emission spectrum for elements?
a quantum release of energy as electrons drop back to their ground state
The quantum theory of energy levels within atoms was aided by:
emission line spectra of various elements
What is meant by "the energy of an electron is quantized"?
Each electron around an atom has a discrete amount of energy.
What is the maximum number of electrons in the following energy level? n = 1
2
What is the maximum number of electrons in the following energy level? n = 2
8
What is the maximum number of electrons in the following energy level? n = 3
18
What is the maximum number of electrons in the following energy level? n = 4
32
What is the maximum number of electrons found in any energy level of the known elements? (Refer to the periodic table.)
32
What is the theoretical maximum number of electrons in the n = 5 energy level?
50
Complete the sentence. Select all that apply. The use of the term "energy levels" in the text implies:
a quantized amount of energy found at the dfferent levels
n = 1, 2, 3, ...
Scientists have not yet determined exactly why electrons do not collapse into the nucleus.
True
Which requires more energy to move an electron?
from n = 1 to n = 2
Which condition will release more energy when an electron changes levels?
from n = 2 to n = 1
Why do the elements of period 4 start a new cycle of properties after the element argon? Select all that apply.
The electrons in the outermost energy level are primarily responsible for the properties of an element.
Additional electrons after argon begin to fill a sublevel of the n = 4 energy level.
What are energy sublevels?
multiple orbitals of specific magnitude within an energy level
maximum number of electrons = 2
maximum number of electrons = 6
maximum number of electrons = 10
maximum number of electrons = 14
s
p
d
f
Where would the electrons in the 3d sublevel be found?
only in the n = 3 energy level
Where would electrons in the d sublevel be found?
in energy levels > 3
What is the atomic number of the first element to start filling a d sublevel?
21
If an atom has 3 energy levels, how many sublevels should it have?
3
Select the correct electron configuration for Vanadium. (Atomic Number 23)
1s^22s^22p^63s^23p^64s^23d^3
The sequence of filling the electron configuration of the elements is not indicated in the periodic table.
False
A principal quantum number refers to:
the numbered energy levels starting from the nucleus outward
The maximum number of energy sublevels found in any energy level is:
4
The maximum number of electrons in a p sub-level is:
6
The 3 in 4p3 represents:
the number of electrons
Which of the following electron configurations for neutral atoms is correct?
nitrogen: 1s2, 2s2, 2p3
Name the element that corresponds to the following electron configuration. 1s2, 2s2, 2p1
boron
Consider the two electron arrangements for neutral atoms A and B. What is the atomic number of A?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
11
Consider the two electron arrangements for neutral atoms A and B. What is the atomic number of B?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
11
Consider the two electron arrangements for neutral atoms A and B. Are atoms A and B the same element?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
Yes
Consider the two electron arrangements for neutral atoms A and B. What is the difference between atom A and atom B?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
The outer electron of atom B has moved to a higher energy state.
Consider the two electron arrangements for neutral atoms A and B. The outer electron of atom B has moved to a higher energy state. What could cause this difference?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
Atom B has absorbed energy, perhaps by heating.
Consider the two electron arrangements for neutral atoms A and B. Which atom is more stable?
A - 1s2, 2s2, 2p6, 3s1
B - 1s2, 2s2, 2p6, 5s1
A
What does the p mean in 1s22s22p63s1?
one of the 4 sub-shells
Which statement applies to the electron at state 2?
It possesses greater energy than the ground state.
What is the atomic number of the first element to start filling an "f" sub-level?
58
Complete the chart. (Remember to enter a "0" if necessary.)
Atomic Number: 3
1s: 2
2s: 1
2p: 0
3s: 0
3p: 0
4s: 0
3d: 0
4p: 0
5s: 0
Complete the chart. (Remember to enter a "0" if necessary.)
Atomic Number: 19
1s: 2
2s: 2
2p: 6
3s: 2
3p: 6
4s: 1
3d: 0
4p: 0
5s: 0
The electron configuration of Ne is:
1s22s22p6
The electron configuration notation for Na is:
1s22s22p63s1
The electron configuration of atoms of a noble gas would be:
1s22s22p6
The number of valence electrons for 1s22s22p4 is:
6
The energy necessary to overcome the attractions of electrons to the nucleus of an atom so as to remove electrons from the atom is called charging energy.
False
A charged atom or particle is called a(n) _______.
Ion
If the valence electrons were removed, what would be the ion charge of the element? Na = _____
+1
If the valence electrons were removed, what would be the ion charge of the element? Mg = _____
+2
If the valence electrons were removed, what would be the ion charge of the element? Al:
+3
How is E related to a period of elements?
E generally decreases from right to left.
Electrons located in the outermost shell of an atom are called ____________.
Valence
____ + e - → Cl-
Cl
Na → Na+ +
1e-
The reactiveness of nonmetals depends on the atom's ability to ________________ electrons.
Gain
Select the number of valence electrons for nitrogen
5
Select the number of valence electrons for hydrogen.
1
Select the number of valence electrons for carbon.
4
Determine the number of valence electrons for sodium through the use of this table. Na:
1
Determine the number of valence electrons for magnesium through the use of this table. Mg:
2
What is the electron configuration when the valence electrons are removed from each of the elements listed in the chart?
1s22s22p6
Using the periodic table, find the neutral atom that has the same electron configuration as 1s22s22p6.
Neon
When all Group IIA elements lose their valence electrons, the remaining electron configurations are the same as for what family of elements?
Family 8, the Noble Gases
How is the ionization energy, E, related to a group of elements?
E decreases from top to bottom.
Why does the ionization energy change when moving down a group of elements?
The attractive force decreases as the atom gets larger.
Using the ideas from this section and the periodic table, choose the more reactive metal. Cs or Na
Cs
Using the ideas from this section and the periodic table, choose the more reactive metal. K or Cu
K
Using the ideas from this section and the periodic table, choose the more reactive metal. Al or Zn
Zn
Using the ideas from this section and the periodic table, choose the more reactive nonmetal. F or Cl
F
Using the ideas from this section and the periodic table, choose the more reactive nonmetal. C or F
F
Using the ideas from this section and the periodic table, choose the more reactive nonmetal. P or O
O
Click on the diagram to choose which atom is more reactive.
https://goalac.owschools.com/media/o_chm_2015/4/shell2.gif
Click on the diagram to choose which atom is more reactive. Hint: These are nonmetals. Which is going to gain a full valence shell of 8 electrons the easiest?
https://goalac.owschools.com/media/o_chm_2015/4/shell4.gif
Which energy level requires the most energy to remove an electron?
the innermost shell
Ionization energy is required to remove an electron from an atom.
True
What does the symbol "E3" represent?
the energy required to remove the third valence electron
The two common units of E are electron volts and Kcal/mole.
True
How does the complete filling of a subshell affect E?
produces chemical stability; therefore increases E
The elements with the highest ionization energy, and thus the lowest reactivity, are:
noble gases
The atomic number of the atom which does not usually form compounds is:
18
The first four ionization energies for an imaginary element, Xz, are E1 = 102 kcal, E2 = 186 kcal, E3 = 4021 kcal, and E4 = 4862 kcal. The number of valence electrons most probable as indicated by this ionization data is:
2
How is ionization energy, E, related to a group of elements?
E decreases from top to bottom.
What factor(s) may be responsible for the ionization energy within a period?
Select all that apply.
The diameter of the atom decreases somewhat as electrons are added.
The attractive force of the nucleus increases.
Using the periodic table, choose the more reactive metal. Al or Mg
Mg
Using the periodic table, choose the more reactive metal. Ta or V
Ta
Using the periodic table, choose the more reactive metal. Cs or Sr
Cs
Using the periodic table, choose the more reactive nonmetal. Si or S
S
Using the periodic table, choose the more reactive nonmetal. Te or O
O
Using the periodic table, choose the more reactive nonmetal. Si or N
N
Theoretically, which metal should be the most reactive?
Francium
Ionization energy is required to add an electron to a neutral atom.
False
What does this symbol, 1/0n, mean?
a neutron of zero charge and one unit of mass
An unstable nucleus which starts a decay process is called the parent nuclide.
True
The nuclear product of radioactive decay is called the offspring nuclide.
False
An alpha particle is equivalent to a hydrogen nucleus.
False
The time required for a radioactive mass to reduce by a factor of 2 is called:
Half-life
It is not possible to determine exactly when a particular unstable isotope will begin to decay.
True
The half-lives of isotopes are all measured in millions of years.
False
How long will it take for half of Bismuth-214 to decay to lead? (Refer to the Uranium-238 decay chain series.)
20 min
Carbon-14 naturally decays to carbon-12.
True
Since carbon-14 decays at a steady rate, it is a reliable method to determine the age of rock samples.
False
What is the significance of the discovery E = mc2?
Mass and energy can convert to one another.
The combining of the nuclei of atoms is known as nuclear fission.
False
The splitting apart of atomic nuclei is known as fission.
True
The daughter products of nuclear explosions produce heavy, but stable isotopes of uranium.
False
Where does the energy come from in this fusion reaction? (https://goalac.owschools.com/media/o_chm_2015/4/21h1.gif)
a small amount of mass converted to energy
The nuclear product of radioactive decay is called the daughter nuclide.
True
A gamma ray emission results in the release of energy without any apparent change in mass or nuclear charge.
True
The half-lives of unstable isotopes vary from milliseconds to billions of years.
True
The combining of atoms is known as nuclear fusion.
True
Iodine-131 is used to
detect thyroid malfunction.
Research has shown that the electrons orbit the nucleus in circular motions as shown on the classic Bohr model.
False
Select the factor(s) that may be responsible for the ionization energy within a period.
The diameter of the atom decreases somewhat as electrons are added.
The attractive force of the nucleus increases.
The Law of Definite Proportions states that substances combine in predictable proportions and that excess reactants remain unchanged.
True
Which of the following radioactive emissions is the most penetrating?
Gamma rays
The person given credit for the first modern atomic theory was __________.
Dalton
A horizontal row of elements in the periodic table represents a _____________.
period
Which element in Period 5 is the most active metal?
Rb
How many electrons will metals generally have in their outer shell?
1-3
Complete the chart. (Remember to enter a "0" if necessary.)

Atomic Number: 10
1s: 2
2s: 2
2p: 6
What is the electron structure of sodium?
1s22s22p63s1
According to the following electron structure, how many valence electrons do these fluorine atoms have?
F = 1s22s22p5
7
When the elements of Group 2 lose their valence electrons, what would be their charge?
+2
Using the periodic table, choose the more reactive metal. Ca or Ra
Ra
Using the periodic table, choose the more reactive nonmetal. At or Br
Br
Using the periodic table, choose the more reactive nonmetal. Br or As
Br
An atom which gains or loses one or more electrons is called a(n) _________.
Ion
A beta particle is equivalent to an electron.
True
J. J. Thomson is credited with the discovery of:
Electrons
What does the 4 indicate in 1s22s22p4?
4 electrons
The emission of a Beta particle has the effect of:
no change in mass
Which of the following electron configurations for neutral atoms is correct?
argon: 1s22s22p63s23p6
When does the electron shown release the greatest amount of energy as it moves from one level to another?
S.1 to G.S
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