"Chemistry can be a good and bad thing. Chemistry is good when you make love with it. Chemistry is bad when you make crack with it." -Adam Sandler
Chemistry is a subject that can be studied during secondary school or at a university as part of further education.
Some have chosen to learn more about chemistry due to the fact that they enjoyed the basic concepts and wish to expand their knowledge on the subject. While others were forced to study this topic throughout the last years of secondary school.
In all honesty, studying chemistry is an acquired taste. Not all will appreciate this scientific discipline that involves the examination of elements, compounds composed of atoms, molecules and ions. The understanding of their composition, structure, properties and behaviours may be one individual's cup of tea and another person's worst nightmare.
Nevertheless, studying basic chemistry concepts has many advantages due to the fact that it is known as central science since it combines mathematics, physics, biology and medicine. The field of chemistry is quite expansive with many different practices that can be studied which cover a lot of interesting topics that will deeply intrigue any science enthusiast. You can read more about key chemistry terminology in our dedicated article!
Without further ado, Superprof will discuss a few of the basic concepts of chemistry such as chemical reactions, the elements, Lewis structure, periodic table and liquids & gases just to name a few.
It does not matter if you love science or not, this article will instruct any individual on the fundamentals of chemistry and provide them with the ability to hold their own if the topic comes up in a conversation!
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Chemical reactions are experienced all the time. Whether you are cooking, making a fire or breathing a chemical reaction is provoked.
In a chemical reaction, the molecules or ions are rearranged and shaped into a new structure. The atomic nucleus remains untouched and only the electrons are transferred to form chemical bonds. The number of atoms from the elements does not change and remain the same from the beginning to the end of the chemical reaction. This was the discovery of a certain Antoine Lavoisier, about whom you can learn more in our piece on the most famous chemists ever.
It is very important to note that chemical reactions are different from physical changes and the most notable difference is that in a chemical reaction the atoms form new products, molecules and compounds whereas in a physical change the atoms retain their same arrangement as before.
It is impossible to notice the molecular change of a chemical reaction in plain sight. Nevertheless, there are signs that help individuals notice the difference such as temperature change, bubbles or colour change.
The atoms and molecules that interact with each other are called the reactants and the atoms and molecules that are produced by the reaction are referred to as products. Therefore the chemical equation would be as follows:
reactant1 + reactant2 + ... -----> ... product1 + product2 + ...
Those who have studied chemistry and have a base of chemical reactions can write the equation in a short-hand version:
a A + b B + ... -----> c C + d D + ...
Chemical reactions can be divided into four different types:
- Synthesis or direct combination,
- Single replacement,
- Metathesis or double displacement.
There are so many examples of different chemical reactions that can be observed on a daily or weekly basis. Here are some of the most noticeable examples:
- Lighting a fire or creating a flame,
- Baking any cake or baked goods,
- Boiling, frying or scrambling an egg,
- Seeing bananas rot,
- Grilling a hamburger patty.
What we have now considered is just the tip of the iceberg. There is so much to learn about chemical reactions. If this section has interested you and you have a desire to learn more, please visit this informative website.
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Elements and the Periodic Table
A chemical element is a pure substance in its simplest form that cannot be broken down any further.
Scientists have so far discovered 118 chemical elements. 94 of these elements are known to commonly occur in nature and the remaining 24 are synthetic and have been man-made.
The most plentiful element in our universe is hydrogen and on the Earth it's iron. The human body and earth's most common element is oxygen.
An element has a single atom and is characterized by its number of protons in the nuclei of its atoms. This is known as the atomic number and is indicated by the number Z.
Elements that are not mixed and are in their purest state all have the same number of protons. Whereas those that are considered mixtures have different protons and atoms.
There are only a couple of elements that are completely pure and have not been combined. These include copper, silver, gold and sulfur to name just a few. Whereas an example of a mixed element would be atmospheric air which is a mixture of nitrogen, oxygen and argon.
Examples of different elements can be observed on the periodic table. The first element, with only one proton, is hydrogen. The second element is helium with two protons and the third is lithium with three protons. The elements and number of protons keep going on the periodic table until it arrives at 118 which is the recently discovered element of oganesson.
The periodic table is the most commonly used arrangement of elements. Elements are organized and divided by atomic number, electron configuration and recurring chemical properties. Table rows are called periods and columns are referred to as groups.
There are 18 groups or columns on the periodic table that have been created to place elements with similar chemical behaviours in the same place. Only seven of the 18 groups have accepted a name for themselves:
- Group 1: Alkali metals,
- Group 2: Alkaline earth metals,
- Group 15: Pnictogens,
- Group 16: Chalcogens,
- Group 17: Halogens,
- Group 18: Noble gases.
The background colours of the elements identify the subcategory in the metal, metalloid and non-metal trend. There are a variety of periodic tables and colours are not standardized. It mostly depends on personal preference, however, categories are kept the same.
Learning more about the periodic table can be extremely interesting and help individuals with the ability to understand the use of different elements.
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Chemical Bonding and the Lewis Structure
Chemical bonding is the attraction between atoms, ions and molecules that allows the formation of chemical compounds. The bonds have different strengths due to the fact that some are stronger such as covalent, ionic and metallic bonds and others are weaker like dipole-dipole interactions, the London dispersion force and hydrogen bonding.
The stronger bonds that hold molecules together are considered permanent whereas the weaker bonds are temporary and break apart after a while. It does not matter how strong the bond is, they are necessary for the chemistry of our own bodies and life itself.
Scientists have discovered that the most common reason why chemical bonds are formed is that atoms are trying to reach their most stable energy level that they can.
In chemistry, and in life, opposites attract. The attraction of the negatively charged electrons that are circling the nucleus and the positively charged protons that are inside the nucleus provokes a pull that creates a chemical bond.
There are various types of chemical bonds that can be observed. Here they are:
- Ionic bonds: these are formed between ions with opposite charges. An example of this is table salt. The positively charged sodium ions and the negatively charged ions are attracted to each other and create sodium chloride.
- Covalent bonds: atoms become more stable by sharing electrons rather than losing or gaining them. Covalent bonds are much more common than ionic bonds in the molecules of living organisms. The more electrons shared between two atoms, the stronger the covalent bond will be.
- Polar Covalent bonds: in this type of bond electrons are unequally shared by the atoms and spend more time close to one another. Due to the unequal distribution of electrons between atoms the charges develop in different parts of the molecule.
- Nonpolar Covalent bonds: these are formed between two atoms of the same element or between atoms of different elements that share electrons equally.
- Hydrogen bonds: polar covalent bonds that have hydrogen contain a slight positive charge due to the fact that the electrons are pulled toward the other element. As a result of this pull, the hydrogen will be attracted to any negative charges and this is called a hydrogen bond.
Lewis Dot Structure
The Lewis dot structures show the bonding between atoms and molecules and the lone pairs of electrons that may exist in the molecule.
This structure was introduced in 1916 by Gilbert N. Lewis in his article titled, The Atom and the Molecule. The Lewis dot structure expanded on the concept of the electron dot diagram by adding some lines to represent the shared pairs in a chemical bond.
It is a quick and easy way to show the valence electron configuration of separate atoms when no previous connections or bonds have been made.
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Acidity and Basicity
Substances can either be determined as an acid or a base. An acid-base reaction is a common chemical reaction between an acid and a base. It can be used to determine the pH of a substance or liquid.
Many scientists have created their own acid-base theories to calculate pH levels, correctly define the substances and carefully observe the reactions.
Svante Arrhenius Acids and Bases
This theory of acids dates back to 1884 and is one of the most commonly referred to today. Arrhenius spent most of his time observing salt and its changes when put into water. In this theory of acids, water is required, only protic acids are permitted which are required to produce hydrogen ions, only hydroxide acids are allowed, acids produce H+ ions in aqueous solutions and bases produce OH- ions in liquids.
Gilbert Newton Lewis Acids and Bases
This is known as being the least strict acid theory due to the fact that only electron pairs are examined and protons are completed left out. The basic concepts of this theory include the fact that acids are electron pair acceptors and that bases are electron pair donors.
Brønsted-Lowry Theory of Acids
Acid-base reactions are described as an acid releasing a proton and a base accepting a proton. Some of the characteristics of this theory are that acids are proton donors, bases are proton acceptors, water-based solutions are acceptable, bases other than hydroxides are acceptable by all and only protic acids are acceptable.
Acids have different properties and can be distinguished by their sour taste, corrosive behaviour, water solutions conduct electric currents and they react with bases to create salts and water. These are just a few of the properties, acids can be determined in other ways also.
Bases can be differentiated from acids if the taste is bitter, feel slippery or soapy and they don't change the colour of litmus (a blue vegetable dye).
Different types of acid that can be observed regularly are:
- Citric acid,
- Lactic acid,
- Carbonic acid,
- Absorbic acid.
Some examples of the most common bases include:
- Household ammonia.
Acids and bases can be studied more thoroughly by learning additional information about the previously mentioned theories.
Chemistry can be a very diverse and intriguing subject to grasp. If this scientific topic interests you, it is important to note that the basic concepts can be analyzed by yourself in the comfort of your own home. If you are pondering which scientific discipline to research, chemistry is the correct one to choose!