Matter Interactions Unit Test
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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)
potassium (K)
potassium (K)
krypton (Kr)
krypton (Kr)
selenium (Se)
selenium (Se)
To determine which element has the same number of valence electrons as bromine (Br), we need to look at the periodic table.
Bromine (Br) is in Group 17, also known as the halogens. The halogens have 7 valence electrons.
From the given options, the element with the same number of valence electrons as bromine is chlorine (Cl), as it is also in Group 17 and has 7 valence electrons.
To determine which element has the same number of valence electrons as bromine (Br), you can refer to the periodic table.
First, locate bromine (Br) on the periodic table. Bromine is in Group 17, also known as the halogens.
Next, look for other elements in Group 17 to find the one with the same number of valence electrons. Valence electrons are the electrons in the outermost energy level of an atom, and they determine the element's chemical properties.
In this case, the element chlorine (Cl) is in the same group as bromine (Br) and therefore has the same number of valence electrons. So, the correct answer 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 correct answer is: They have similar reactivity.
Sodium (Na) and potassium (K) belong to Group 1 on the periodic table, also known as the alkali metals. Elements in this group have similar chemical properties and reactivity due to their single valence electron. Sodium and potassium both have one valence electron, making them highly reactive and prone to forming ions with a charge of +1. This similarity in reactivity is why they are placed in the same group on the periodic table.