AnswersChemistry Honors AUnit Test

Unit Test — Unit test Answers

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When electrons are removed from the outermost shell of a calcium atom, the atom becomes

A
an anion that has a larger radius than the atom.
B
an anion that has a smaller radius than the atom.
C
a cation that has a larger radius than the atom.
D
a cation that has a smaller radius than the atom.
2
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A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?

A
V
B
Na
C
Mg
D
Se
3

How did Niels Bohr describe electrons in his atomic model?

A
Their energies can have any values.
B
Their exact positions cannot be known.
C
They have high probability to be found in certain regions.
D
They orbit the central nucleus in discrete paths.
4

Which of Dalton's ideas about the atom did J.J. Thomson's experiment disprove?

A
It disproved that atoms are divisible.
B
It disproved that atoms are indivisible.
C
It disproved that atoms contain protons.
D
It disproved that atoms contain electrons.
5

Which set of numbers gives the correct possible values of l for n = 2?

A
0
B
0, 1
C
0, 1, 2
D
0, 1, 2, 3
6

To show the electron configuration for an atom, when would it be better to use an orbital notation than to use a written configuration with numbers, letters, and superscripts?

A
when the aim is to use less space
B
when the aim is to show electron spins
C
when the aim is to show orbital shapes in subshells
D
when the aim is to show electron distributions in shells
7

Which pure substance can be classified as an element?

A
H2
B
NO3
C
NaCl
D
H2SO4
8

Which describes Ernest Rutherford’s experiment?

A
Positive particles are fired at gold foil. Most bounce back, but some pass through.
B
Negative particles are fired at gold foil. Most bounce back, but some pass through.
C
Positive particles are fired at gold foil. Most pass through, but some bounce back.
D
Negative particles are fired at gold foil. Most pass through, but some bounce back.
9

The diagram below shows some subatomic particles.Which of these statements best identifies the particle that is labeled with an X?

Question illustration
A
It is either a nucleus or a proton.
B
It is either a proton or a neutron.
C
It is either a neutron or an electron.
D
It is either an electron or a nucleus.
10

Which element is the most reactive?

A
sodium
B
nickel
C
carbon
D
oxygen
11

Which substance is a mixture?

A
table salt
B
gasoline
C
aluminum
D
carbon dioxide
12

Iron, an element with the chemical symbol Fe, is an important element. It is used to make steel and is part of the substance that transports oxygen throughout the human body.Which statement about Fe is supported by the modern atomic theory but not John Dalton’s theory?

A
The element iron is composed of small particles called atoms.
B
The electrons of iron have probable locations in a region of space around the nucleus.
C
Iron atoms combine with other atoms in whole number ratios to form compounds.
D
Chemical reactions that involve iron do not create new atoms of iron.
13

Which element has the largest atomic radius?

A
As
B
N
C
P
D
Sb
14

In which orbitals would the valence electrons for selenium (Se) be placed?

A
s orbital and f orbital
B
s orbital only
C
s orbital and p orbital
D
d orbital only
15

Which element is classified as an alkali metal?

A
Rb
B
Sr
C
Zr
D
Cl
16

Which statement best describes how electrons fill orbitals in the periodic table?

A
Electrons fill orbitals in order of their increasing energy from left to right.
B
Electrons fill orbitals in order of their increasing energy from right to left.
C
Elements fill orbitals in order of increasing energy from top to bottom in each group.
D
Elements fill orbitals in order of increasing energy from bottom to top in each group.
17

How many valence electrons does aluminum (Al) have available for bonding?

A
1
B
2
C
3
D
4
18

Who was the first to propose the existence of atoms?

A
John Dalton
B
Democritus
C
Joseph Proust
D
Ernest Rutherford
19

Air is made up of different gases, such as oxygen, nitrogen, and carbon dioxide. Which statement best describes these three components of air?

A
Oxygen, nitrogen, and carbon dioxide are all classified as pure substances.
B
Oxygen, nitrogen, and carbon dioxide cannot react with another substance.
C
Oxygen, nitrogen, and carbon dioxide are chemically bonded to one another.
D
Oxygen, nitrogen, and carbon dioxide can be classified as elements.
20

Hydrogen has three isotopes 1H, 2H, and 3H. What is the difference between these three isotopes?

A
The number of protons ranges from 1 to 3.
B
The number of electrons ranges from 1 to 3.
C
The number of neutrons ranges from 0 to 2.
D
The number of protons ranges from 0 to 2.

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