High school

When did I realise I was having fun with Chemistry?

After that incredible first chemistry lecture and those exciting questions, I started looking at everything around me slightly differently. In particular I started thinking how actually human behaviour is nothing more than electric impulses operated by chemicals released in our brains. This buzzing thought was leaving not much space for what we can call feelings, which I started to reduce to mere reactions to an imbalance in what is our normal chemical composition. Despite all these wonderings, I still did not have any proper knowledge about Chemistry and Biology to help me figure out how things actually work.

Eventually, we started exploring the inorganic chemistry from what we can call scratches: from the atomic structure, to the electron configuration and the periodic table, up to how atoms can be combined to become molecules and the different types of chemical bonds and redox reactions. Obviously, being in high school did not allow my Chemistry teacher to go into deep, but all these topics were incredibly fascinating to me: understanding the principles behind the formation and the structure of matter was starting to make me feel like there might actually be an order in life, which for a 15 years old teenage girl dealing with the issue of adolescence can be quite reassuring.

Just before Christmas our teacher announced that we would have had a test once back to school from the holidays. I spent my Christmas time revising and exercising and I think that preparing that test was the thing that excited and scared me the most during my studying years. But hard work and particularly curiosity and interest were very well repaid with an incredibly good mark.

That day I finally felt something new that I never felt before in my academic career: a feeling of satisfaction for all the effort I made and the recognition that my genuine interest was leading me to properly understand principles and mechanisms. I think that day I started to realise that was the path I actually wanted to purse in my life.

What I was particularly fascinated by and I was quite enjoying solving were redox reactions.

“Science Related Fact” (SRF):

Redox reactions are everywhere and generally involve the transfer of electrons between chemical species. As an example, batteries in our electronic devices rely on these reactions, as well as our bodies that use redox reactions to transform food and oxygen into energy, producing on the side water and CO2 which we then exhale. To explain and simplify how redox reactions work I would like to talk again about table salt.

Table salt is composed by an atom of sodium (Na) and an atom of chlorine (Cl) forming what is called sodium chloride, with the molecular formula NaCl. To understand how these two elements form the table salt, we will briefly talk about their characteristics: Na is an alkali metal in the first group of the periodic table and has therefore the tendency to get rid of the outermost electron to gain the electron configuration of the noble gas that precedes it in the periodic table (as noble gasses are incredibly stable). On the other side, chlorine is a halogen that belongs to the second-last group of the periodic table, close enough to a noble gas to be eager to gain one last electron to reach the electron configuration of the noble gas just in front of it (see figure below).

“Periodic table of elements”, different groups (elements with similar chemical behaviours) and periods (elements show a decreased radius moving left to right) are shown. Sodium (Na) and chlorine (Cl) are highlighted. The sodium chloride redox reaction has been made explicit on top of the periodic table.

Since “free” electrons do not exist, in a redox reaction there must be a chemical element that will lose an electron and another element that will gain it. Therefore, not only one needs to balance all the elements in the reaction (Na and Cl in this case), but also all the electrons lost by the Na must be equal to the electrons gained by the Cl (see figure above for the main equation and the two semi-reactions showing the electrons movement).

However simplified this example is, it presents the main characteristics of redox reactions, that, to sum up, are: the movement of electrons from one element to the other, the direction of this movement that depends on which of these elements has a higher attraction for them and, last and most important point, the lost and gain of electrons is a simultaneous process.

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