Answers26-27 WHS-Chemistry-1stSixWeeksAtomic Numbers and Electron Configurations

Atomic Numbers and Electron Configurations — Unit test Answers

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1
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How are isotopes defined?

A
forms of different elements that have the same number of neutrons in each atom
B
forms of different elements that have the same number of protons in each atom
C
forms of the same element that differ in the number of neutrons in each atom
D
forms of the same element that differ in the number of protons in each atom
2
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What did J. J. Thomson observe when he applied electric voltage to a cathode ray tube in his famous experiment?

A
The stream of cathode ray particles was moving very slowly.
B
The glass opposite of the negative electrode started to glow.
C
The electric voltage had little effect on the stream of particles.
D
The tube contained two pieces of metal that served as electrodes.
3

Who reported four “element” classifications, but included some substances that were combinations of elements rather than true elements in his listing?

A
Henry Moseley
B
Dmitri Mendeleev
C
Antoine Lavoisier
D
Johann Dobereiner
4

Which of these properties is the best one to use for identification of an element?

A
the number of neutrons in the atomic nucleus
B
the number of protons in the atomic nucleus
C
the number of isotopes that are formed by the element
D
the number of charges on ions of the element
5

The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have?

A
24
B
28
C
76
D
80
6

Which is a correct comparison between the modern quantum model and John Dalton’s model of the atom?

A
The modern model is not as widely accepted by scientists as Dalton’s model.
B
The modern model states that atoms of all elements are identical, whereas Dalton’s model does not.
C
The modern model recognizes particles in the atom, whereas Dalton’s model does not.
D
The modern model does not explain emission spectra, whereas Dalton’s model does.
7

Which diagram best illustrates the atomic model that Rutherford derived from his gold foil experiment?

A
A small orange circle with seven plus signs is at the center of a larger dotted circle. Between the two circles are 7 small green circles, each labeled with a negative sign.
Option A
B
A red circle with a large, faint plus sign visible contains 10 small orange circles labeled with minus signs.
Option B
C
An orange circle bounded by a heavier, darker orange line surrounds the word Atom.
Option C
D
A small blue circle labeled with a minus sign lies at the center of a larger circle. Spaced around the outer circle are three small green circles labeled with plus signs.
Option D
8

Which property would xenon most likely have?

A
It is stable.
B
It is a solid.
C
It is flammable.
D
It is silver in color.
9

The table below gives the data that is needed to calculate the average atomic mass of element B.IsotopeAtomic mass (amu)Relative abundance (%)B-1010.0119.91B-1111.0180.09Based on these data, what is the average atomic mass of element B?

A
10.01
B
10.51
C
10.81
D
11.01
10

Which element would most likely have chemical properties similar to that of magnesium (Mg)?

A
Ar
B
Ca
C
F
D
Ni
11

How many electrons can the n = 4 shell hold?

A
8
B
16
C
32
D
64
12

Which is a component of John Dalton’s atomic theory?

A
The ratio of atoms in a compound can vary.
B
The atoms of a single element differ.
C
An atom is a small particle that cannot be broken down.
D
Atoms of different elements can be identical.
13

Which statement best describes the light that will cause emission of electrons from a given metal through the photoelectric effect?

A
light with a low enough intensity
B
light with a high enough frequency
C
light with a high enough intensity
D
light with a low enough frequency
14

What was Johann Dobereiner’s contribution to the development of the periodic table?

A
He arranged the elements according to increasing atomic mass.
B
He arranged the elements according to increasing atomic number.
C
He identified triads of elements that had similar properties.
D
He organized elements into four groups based on their properties.
15

Which scientist’s law about the ratios of masses of elements in a compound did John Dalton’s work on the atomic structure help to explain?

A
Democritus
B
J. J. Thomson
C
Ernest Rutherford
D
Joseph Proust

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