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 27 neutrons.
The model should show 27 protons and 27 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 32 neutrons.
The model should show 27 protons and 32 neutrons.
The model should show 32 protons and 59 neutrons.
The model should show 27 protons and 32 neutrons.
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 .
A molecular model of lithium sulfide would have two spheres.
A molecular model of lithium sulfide would have two spheres.
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.
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
krypton (Kr)
krypton (Kr)
potassium (K)
potassium (K)
selenium (Se)
selenium (Se)
chlorine (Cl)
Chlorine (Cl) has the same number of valence electrons as bromine (Br).
Why are sodium (Na) and potassium (K) in the same group on the periodic table?(1 point)
Responses
They have similar reactivity.
They have similar reactivity.
They are both hard and brittle.
They are both hard and brittle.
They have similar atomic weights.
They have similar atomic weights.
They are both colorless.
They are both colorless.
They have similar reactivity.
Which of the following is considered acidic?(1 point)
Responses
Lime Water
Lime Water
Ammonia
Ammonia
Vinegar
Vinegar
Soap
Soap
Vinegar is considered acidic.
The chemical formula for carbonic acid is H2CO3
. How many compounds are represented by this formula?(1 point)
Responses
1
1
2
2
6
6
3