Answer: The correct answer is the option: B. An element with eight valence electrons is chemically unstable.
Explanation:
Hello! Let's solve this!
We will analyze each of the options:
A. The group number of the element provides a clue to the number of valence electrons: it is correct, since it provides the number of valence electrons.
B. An element with eight valence electrons is chemically unstable: this is not correct, since elements with eight electrons in the valence shell cannot react because they already have the last complete shell. Therefore, they are chemically stable.
C. The points must be placed one at a time on each side of the chemical symbol: it is correct, because that is the way to make the point diagram.
D. An atom is chemically stable if all the points are paired: this is correct since this verifies that the point diagram has been done well.
We conclude that the correct answer is the option: B. An element with eight valence electrons is chemically unstable.
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Methylene chloride is less dense than water
Answer:
A molecular compound is usually composed of two or more nonmetal elements. Molecular compounds are named with the first element first and then the second element by using the stem of the element name plus the suffix -ide.
Answer:
2HNO3 (aq) + Na2CO3 (aq) → 2NaNO3 (aq) + CO2 (g) + H2O (l)
Explanation:
This question is asking to write and balance an equation between between aqueous sodium carbonate (Na2CO3) and aqueous nitric acid (HNO3). The equation is as follows:
HNO3 (aq) + Na2CO3 (aq) → NaNO3 (aq) + CO2 (g) + H2O (l)
However, this equation is not balanced as the number of atoms of each element must be the same on both sides of the equation. To balance the equation, one will make use of coefficients as follows:
2HNO3 (aq) + Na2CO3 (aq) → 2NaNO3 (aq) + CO2 (g) + H2O (l)