# What are some common mistakes students make when drawing Lewis structures?

May 30, 2018

Just to retire this question....here is one common observation...

#### Explanation:

In AS and A2 level English, you ARE not allowed to take a dictionary of English into the final examination. Likewise in language exams, an English/foreign language dictionary is not permitted. In an exam of chemistry or physics a Periodic Table is not only permitted it is ACTUALLY PROVIDED. And this tells you the atomic number, and atomic masses of ALL the 100 or so known elements...

And the Periodic Table provides more than this....the modern table gives you a pretty shrewd idea of electronic structure...and we even refer to $\text{s-block}$, $\text{p-block}$, and $\text{d-block elements...}$

And so here the mistake is that some students do not use the Periodic Table effectively...even in an A2 exam or undergrad exam you are going to get questions that ask what is the atomic number of a given element, or what are the numbers of neutrons in ""^56Fe...and these questions are money for jam with a Table beside you...

And so if you have to draw a Lewis structure, with a Table beside you, GETTING the wrong number of valence electrons should not be a capital punishment, but almost....