Matter Interactions Unit Test
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Question
Cobalt has a mass number of 59 and an atomic number of 27. A student wants to create a model of a cobalt atom. Which statement about the model is correct?(1 point)
Responses
The model should show 27 protons and 32 neutrons.
The model should show 27 protons and 32 neutrons.
The model should show 32 protons and 59 neutrons.
The model should show 32 protons and 59 neutrons.
The model should show 59 protons and 27 neutrons.
The model should show 59 protons and 27 neutrons.
The model should show 27 protons and 27 neutrons.
The model should show 27 protons and 27 neutrons.
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The correct statement about the model of a cobalt atom is: The model should show 27 protons and 32 neutrons.
Question
In a molecule of lithium sulfide, there are two atoms of lithium and one atom of sulfur. Which statement about lithium sulfide is correct?(1 point)
Responses
The chemical formula for lithium sulfide is LiS2.
The chemical formula for lithium sulfide is LiS 2 .
Both lithium and sulfur form positive ions.
Both lithium and sulfur form positive ions.
The atoms in lithium sulfide are held together by bonds.
The atoms in lithium sulfide are held together by bonds.
A molecular model of lithium sulfide would have two spheres.
The correct statement about lithium sulfide is: The atoms in lithium sulfide are held together by bonds.
Matter Interactions Unit Test
3 of 133 of 13 Items
Question
Use the periodic table to answer the question.
An illustration shows the periodic table.
Which element has the same number of valence electrons as bromine (Br)?
(1 point)
Responses
chlorine (Cl)
chlorine (Cl)
krypton (Kr)
krypton (Kr)
selenium (Se)
selenium (Se)
potassium (K)
potassium (K)
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The element that has the same number of valence electrons as bromine (Br) is chlorine (Cl).
Why are sodium (Na) and potassium (K) in the same group on the periodic table?(1 point)
Responses
They are both colorless.
They are both colorless.
They are both hard and brittle.
They are both hard and brittle.
They have similar reactivity.
They have similar reactivity.
They have similar atomic weights.
The reason why sodium (Na) and potassium (K) are in the same group on the periodic table is because they have similar reactivity.
A student cuts some fabric into two pieces. Is this change physical or chemical?(1 point)
Responses
It is a chemical change because the size changes.
It is a chemical change because the size changes.
It is a physical change because the process is reversible.
It is a physical change because the process is reversible.
It is a physical change because there is no reaction.
It is a physical change because there is no reaction.
It is a chemical change because there is no phase change.
It is a chemical change because there is no phase change.
Cutting fabric into two pieces is a physical change because it is reversible and there is no reaction taking place.
How are chemical changes different from physical changes?(1 point)
Responses
They involve heat.
They involve heat.
They include shifts in the phase of matter.
They include shifts in the phase of matter.
They form new substances.
They form new substances.
They are reversible.