well tested explanation for a broad set of observations

Which discovery did J. J. Thomson make that improved upon Dalton's atomic theory?

Atoms contain tiny, negatively charged electrons.

What is the definition of atomic mass unit?

one twelfth the mass of a carbon atom

The nucleus of an atom is

the central core and is composed of protons and neutrons.

Atomic size generally

decreases as you move from left to right across a period.

In Bohr's model of the atom, where are the electrons and protons located?

The electrons move around the protons, at the center

What is one difference between a mixture and a compound?

A compound can only be separated by chemical means.

Which of the following equals one atomic mass unit?

one-twelfth the mass of one carbon-12 atom

When do ionic compounds conduct electricity?

when melted and dissolved in water

What is the definition of atomic mass?

the weighted average of the masses of the isotopes

What information does a molecular formula provide?

the number and kind of atoms present in a molecule

How is the number of neutrons in the nucleus of an atom calculated?

Subtract the number of protons from the mass number.

Which of the following statements is true?

Protons are positively charged and have a mass of 1 amu.

What is the definition of mass number?

the total number of protons and neutrons in the nucleus

Which of the following is true about subatomic particles?

The mass of a neutron nearly equals the mass of a proton.

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Chemistry Midterm (2017)

70 termsStudBud Administration51 plays

A #chemistry quiz to review first semester

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Questions 70

Answers

1
Which of the following is true about compounds?
have properties similar to those of their component elements
Can be physically separated into their component elements.
They have compositions that vary.
They are substances.
2
Which of the following is true about homogeneous mixtures?
They are known as solutions.
They are always liquids.
They have compositions that never vary.
They consist of two or more phases.
3
Which state of matter has a definite volume and takes the shape of its container?
gas
solid
plasma
liquid
4
What is another name for the transition metals?
noble gases
Group C elements
Group B elements
Group A elements
5
Which of the following is a physical property?
melting point
ability to rust
explosive
combustible
6
How many valence electrons are in an atom of magnesium (Mg)?
5
2
3
4
7
Separating a solid from a liquid by evaporating the liquid is called
filtration
solution
condensation
distillation
8
What is the name given to the electrons in the highest occupied energy level of an atom?
orbital electrons
anions
cations
valence electrons
9
What is the formula of the ion formed when potassium achieves 8 electrons in its outer shell?
K2-
K1-
K+
K2-
10
A theory is a
proposed explanation for an observation
summary of the results of many observations
procedure used to test a proposed explanation
well tested explanation for a broad set of observations
11
Which discovery did J. J. Thomson make that improved upon Dalton's atomic theory?
Atoms that combine do so in simple whole-number ratios.
Atoms contain a tiny, positively charged nucleus.
Atoms contain tiny, negatively charged electrons.
Atoms are always in motion.
12
Which of the following is a chemical change?
fermenting of cheese
melting cheese
mixing two cheeses in a bowl
grating cheese
13
What is the definition of atomic mass unit?
the weighted average of the masses of the isotopes
the total number of protons and neutrons in the nucleus
the number of protons in the nucleus of an element.
one twelfth the mass of a carbon atom
14
How does calcium obey the octet rule when reacting to form compounds?
It does not change its number of electrons.
Calcium does not obey the octet rule.
It gains electrons.
It gives up electrons.
15
The reaction 2Fe+3Cl-->2FeCl₃ is an example of which type of reaction?
combination reaction
combustion reaction
double replacement reaction
single replacement reaction
16
Which of the following elements is in the same period as beryllium?
magnesium
nitrogen
oxygen
carbon
17
What is another name for the representative elements?
transition elements
Group A elements
Group B elements
Group C elements
18
Which of the following is a physical change?
evaporation
explosion
rotting of food
corrosion
19
Which element has the largest electronegativity?
Fluorine
Rubidium
Potassium
Carbon
20
Which of the following is a homogenous mixture?
pasta in water
oil in vinegar
alcohol in water
muddy water
21
The atomic number of an element is the total number of which particles in the nucleus?
neutrons
protons and electrons
electrons
protons
22
The study of processes that take place in organisms.
organic chemistry
physical chemistry
inorganic chemistry
biochemistry
23
The nucleus of an atom is
positively charged and has more protons than neutrons.
negatively charged and has a high density.
the central core and is composed of protons and neutrons.
negatively charged and has a low density.
24
Which of the following correctly represents an ion pair and the ionic compound the ions form?
Pb4-, O2-; Pb2O4
Na-, Cl-; NaCl2
Ba+, O2-; Ba2O2
Ca2-, F-; CaF2
25
Which subatomic particle plays the greatest part in determining the properties of an element?
nucleus
proton
neutron
electron
26
Atomic size generally
remains constant within a period.
decreases as you move from left to right across a period.
increases as you move from left to right across a period.
decreases as you move from top to bottom within a group.
27
In Bohr's model of the atom, where are the electrons and protons located?
The electrons and protons are located throughout the atom
The electrons move around the protons, at the center
The electrons occupy fixed positions around the protons
The electrons and protons move throughout the atom.
28
What is one difference between a mixture and a compound?
A mixture must be uniform in composition.
A mixture can only be separated by chemical means.
A compound can only be separated by chemical means.
A compound consists of more than one phase.
29
Which of the following equals one atomic mass unit?
one-twelfth the mass of one carbon-12 atom
the mass of one carbon-12 atom
the mass of one helium-4 atom
the mass of one electron
30
What is the charge on the oxygen ion?
1-
2+
1+
2-
31
When do ionic compounds conduct electricity?
In solid form
when dissolved in water
when melted and dissolved in water
when melted
32
What is the definition of atomic mass?
one twelfth the mass of a carbon atom
the number of protons in the nucleus of an element.
the weighted average of the masses of the isotopes
the total number of protons and neutrons in the nucleus
33
In an experiment testing the affects of music on plant growth, plant growth is the
controlling variable
manipulated variable
independent variable
responding variable
34
The equation Mg(s)+ 2HCl(aq) -->MgCl₂(aq) +H₂(g) is an example of which type of reaction?
combustion
double replacement
single replacement
combination reaction
35
What is the name given to the electrons in the highest occupied energy level of an atom?
cations
orbital electrons
anions
valence electrons
36
Which of the following pairs of elements is most likely to form an ionic compound?
nitrogen and oxygen
potassium and chlorine
Sodium and magnesium
silicon and phosphourous
37
What information does a molecular formula provide?
the number and kind of atoms bonded by transfer of electrons
information about a molecule’s structure
the number and kind of atoms present in a molecule
the simplest whole-number ratio of atoms that are bonded
38
In carbon-13 what does the 13 represent?
atomic number
atomic mass unit
atomic mass
mass number
39
How is the number of neutrons in the nucleus of an atom calculated?
Add the number of electrons and protons together.
Subtract the number of electrons from the number of protons.
Add the mass number to the number of electrons.
Subtract the number of protons from the mass number.
40
What are the Group 1A and Group 7A elements examples of?
transition elements
representative elements
nonmetallic elements
noble gases
41
Which of the following statements is true?
Electrons are negatively charged and have a mass of 1 amu.
The nucleus of an atom never has a mass of 1 amu.
Neutrons are negatively charged and have a mass of 1 amu.
Protons are positively charged and have a mass of 1 amu.
42
Evidence about Dalton’s atomic theory has shown that
atoms of an element can have different numbers of protons.
atoms are divisible.
all atoms of an element are not identical
all of Dalton's hypotheses were correct.
43
What is the definition of mass number?
the total number of protons and neutrons in the nucleus
the number of protons in the nucleus of an element.
the weighted average of the masses of the isotopes
one twelfth the mass of a carbon atom
44
All atoms are
negatively charged
neutral
positively charged
45
The modern periodic table is arranged in order of increasing atomic ____.
radius
number
mass
charge
46
The equation H₃PO₄+3KOH -->K₃PO₄+3H₂O is an example of which type of reaction?
combination
double replacement
single replacement
combustion
47
Which of the following is true about subatomic particles?
Protons are the lightest subatomic particle.
The mass of a neutron nearly equals the mass of a proton.
Neutrons are the lightest subatomic particle.
Electrons are the heaviest subatomic particle
48
Of the elements Pt, V, Li, and Kr, which is a nonmetal?
Kr
Li
V
Pt
49
Who arranged the elements according to atomic mass predict the properties of missing elements?
Henry Moseley
Dmitri Mendeleev
John Dalton
antoine Lavoisier
50
Which of the following is a heterogeneous mixture?
air
steel
salt water
soil
51
How does atomic radius change from left to right across a period in the periodic table?
It tends to decrease.
It first increases, then decreases.
It tends to increase.
It first decreases, then increases.
52
Which of the following groupings contains only representative elements?
Hg, Cr, Ag
Al, Mg, Li
Ni, Fe, Zn
Cu, Co, Cd
53
The octet rule states that, in chemical compounds, atoms tend to have ____.
more protons than electrons
eight electrons in their outer energy level
more electrons than protons
10 valence electrons
54
Which of the following occurs in an ionic bond?
Like-charged ions attract.
Oppositely charged ions attract.
Two atoms share two electrons.
Two atoms share more than two electrons.
55
An element has an atomic number of 76. How many protons and electrons are there?
76 protons and 0 electrons
76 protons and electrons
152 protons and 76 elements
38 protons and 38 electrons
56
Which state of matter takes both the shape and volume of its container?
solid
liquid
plasma
gas
57
The study of all chemicals containing carbon.
inorganic chemistry
organic chemistry
analytical chemistry
biochemistry
58
When paper turns yellow-brown upon exposure to sunlight, what type of change is taking place?
a chemical change
a physical change
both a physical change and a chemical change
neither a physical change nor a chemical change
59
What happens to matter during a chemical reaction?
Matter is neither destroyed or created.
Some matter is destroyed and some is created.
Some matter is destroyed.
Some matter is created.
60
What is the net charge of the ionic compound calcium fluoride?
1-
2-
1+
0
61
How many valence electrons are in an atom of neon?
8
3
4
2
62
How many electrons does barium have to give up to achieve a noble-gas electron configuration?
3
1
2
4
63
Which state of matter is characterized by having an indefinite shape, but a definite volume?
liquid only
plasma
solid only
gas
64
The quantum mechanical model of the atom
involves the probability of finding an electron in aposition
no longer requires the concept of energy levels.
was proposed by Niels Bohr.
defines the exact path of an electron around the nucleus.
65
Which of the following elements forms an ion with a 1– charge?
potassium (K)
hydrogen (H)
flourine (F)
sodium (Na)
66
The octet rule states that, in chemical compounds, atoms tend to have ____.
the electron configuration of a noble gas
more protons than electrons
seven electrons in their principal energy level
more electrons than protons
67
Why do atoms share electrons in covalent bonds?
to become more polar
to become ions and attract each other
to attain a noble-gas electron configuration
to increase their atomic numbers
68
How does calcium obey the octet rule when reacting to form compounds?
Calcium does not obey the octet rule.
It gives up electrons.
It gains electrons.
It does not change its number of electrons.
69
Which of the following is a chemical property?
color
ability to react with oxygen
freezing point
hardness
70
How do atoms achieve full valence shells in a single covalent bonds?
Two atoms share two pairs of electrons.
One atom loses two electrons to the other atom in the bond.
Two atoms share one electron.
Two atoms share two electrons.

Chemistry Midterm (2017) Flashcards | StudBud