Video Transcript
Which of the following is the correct Lewis structure for an atom of nitrogen?
A Lewis structure, also called a Lewis dot diagram or an electron dot structure, is an illustration that represents the valence electrons of atoms and ions. Lewis structures are a convenient and efficient way to show how valence electrons are shared or transferred between atoms when they form covalent or ionic bonds. To answer this question, we need to determine which of the answer choices is the correct Lewis structure for an atom of nitrogen. So we’ll first need to determine how many valence electrons an atom of nitrogen has.
Valence electrons are the electrons found in the outermost electron shell. The periodic table can be a useful tool to determine the number of valence electrons in a neutral atom of several of the elements. By numbering the columns of the periodic table, skipping the d block, we can determine the number of valence electrons in a neutral atom of all elements in the same group. For example, atoms of the elements in group one, including hydrogen, lithium, sodium, and potassium, have one valence electron, while atoms of elements in group 17, including fluorine, chlorine, and bromine, have seven valence electrons. Nitrogen is found in group 15. So an atom of nitrogen has five valence electrons.
To draw the Lewis structure for an atom of nitrogen, we write the chemical symbol for nitrogen then place dots around the chemical symbol to represent each of the valence electrons. As nitrogen has five valence electrons, we’ll draw a dot representing an electron on each side of the chemical symbol then pair up the fifth dot. This is the Lewis structure for an atom of nitrogen, which we can see matches the structure shown in answer choice (C). Therefore, the correct Lewis structure for an atom of nitrogen is the structure shown in answer choice (C).
