How are atoms and molecules related?

Introduction

Hello to everyone. Do you know what atoms and molecules definition is? Are atoms and molecules the same? We are going to answer this questions. This time we have introduced an activity which stimulates kids imagination and is a great start into the world of organic chemistry for kids. In this article we will:

• describe how are atoms and molecules related
• write about abundance of the chemical elements in the Universe
• introduce the periodic table list of elements
• ignite your child imagination with a colorful activity

Are atoms and molecules the same?

To make it straight forward, the answer is “no”. Atoms and molecules are not the same thing. Following Oxford Dictionary:

• molecules are a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
• atom is the smallest particle of a chemical element that can exist, the word comes from Greek atomos ‘indivisible’.

Let us explain this with two examples.

• First example. We have an atom of oxygen [O symbol] which can create two molecules: normal oxygen made of two atoms of oxygen [ O₂ ] or so called ozone which is a molecule made of three atoms of oxygen [ O₃ ]. They have different chemical properties. Oxygen [ O₂ ] is relatively safe for life, where ozone [ O₃ ] is a colorless unstable toxic gas with a pungent odor and powerful oxidizing properties.
• Second example. Water. The most famous molecule in the world – H₂O. It combines three atoms – two atoms of hydrogen and one atom of oxygen

Atoms and molecules size difference

Molecules can be built with a different number of atoms. The simplest ones contains two atoms, the most complicated molecules are called polymers. They are possible, because carbon atoms are able to form very stable bonds with other carbon atoms. Very well known and one of the largest naturally occurring molecule is DNA (Deoxyribonucleic acid). It is a macro-molecule and can reach macroscopic sizes, so it can be observed with bare eye. To get the scale just check the following fact. The first and largest chromosome in our DNA, which is 247 million base pairs or roughly 15 billion atoms split over the two molecules in the double helix

Abundance of the chemical elements in the Universe

Have you ever wondered what chemical elements occur the most in the Universe and what the abundance is? The abundance of the chemical elements is a measure of the occurrence of the chemical elements relative to all other elements in a given environment. It can be measured in three ways: by mass fraction, by mole fraction and by volume fraction.

Firstly, taking mass fraction of oxygen in water molecule we get 89%, because that is the fraction of water’s mass which is oxygen. While considering mole fraction we get 33,3% because there is only one atom of oxygen out of three atoms in a water molecule; do you remember previous paragraph in our article, where we give an example of H₂O? The last way to measure is by volume fraction. This method is used to measure abundance in mixed gasses. In value, it is very similar to mole fraction.

Coming back to our dilemma – what chemical elements occur the most in the Universe? Taking mass fraction the most common is hydrogen, then we have helium, oxygen and carbon. Below we present a table of top 10 chemical elements occurring in our galaxy – Milky Way.

Atomic number	Element	Mass friction
1	Hydrogen	739000
2	Helium	240000
8	Oxygen	10400
6	Carbon	4600
10	Neon	1340
26	Iron	1090
7	Nitrogen	960
14	Silicon	650
12	Magnesium	580
16	Sulfur	440

The interesting fact is that the fraction proportions between the elements we observe in the Milky Way are almost the same we observe in living structures – for instance in our body. So we can say that the Universe is inside us and we are a part of the Universe – isn’t this a beautiful connection?

Periodic table list of elements

What is periodic table?

In the beginning, before we jump into our activity we would like to dig a little bit deeper into one of the most useful tools in chemistry – period table. It is called also Mendeleev Periodic Table, named after noble Russian chemist – Dmitri Mendeleev. He formulated the Periodic Law, created a farsighted version of the periodic table of elements, and used it to correct the properties of some already discovered elements and also to predict the properties of eight elements yet to be discovered.

The simplest way to describe the table is to show it and explain the basics.

The periodic table is a tabular display of the chemical elements, which are arranged by atomic number (from 1 to 118 on our image), electron configuration, and recurring chemical properties. The structure of the table shows periodic trends. The seven rows of the table, called periods, generally have metals on the left and non-metals on the right. The columns, called groups, contain elements with similar chemical behaviors. There are commonly known 8 groups:

• 1: alkali metals ( Lithium, Sodium, Potassium, Rubidium, Cesium and Francium )
• 2: alkaline earth metals
• 3 – 12: Transition metals
• 13 – 17: Metalloids ( Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium and Polonium )
• 13 – 15: Other metals ( Aluminium, Gallium, Indium, Tin, Thallium, Lead and Bismuth )
• 1, 14, 15, 16: Non-metals ( Hydrogen, Carbon, Nitrogen, Oxygen, Phosphorus, Sulfur and Selenium )
• 17: halogens ( Fluorine, Chlorine, Bromine, Iodine and Astatine )| Group 18: noble gases ( Helium, Neon, Argon, Krypton, Xenon and Radon ) Also displayed are four simple rectangular areas or blocks associated with the filling of different atomic orbitals.

How to read periodic table – example

If you would like to know how heavy and how many electrons and orbits oxygen has, you need to find O symbol and read the periodic table as follows:

• firstly, atomic number (Z) = 8, it means the number of protons found in the nucleus of every atom of that element is 8,
• secondly, oxygen belongs to period 2, so it means it has 2 electron shells,
• thirdly, it belongs to group 16 (called chalcogens)
• last but not least, it belongs to reactive non-metals (represented by the light green color on the table)

There is a lot of variations of periodic tables which contain much more information dependently on the purpose of it. In our article we just present the basics.

Organic chemistry

Organic chemistry is a sub-discipline of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Nevertheless, not all compounds that contain carbon are organic – example: carbon dioxide [CO₂ ].

Organic compounds form the basis of all earthly life and constitute the majority of known chemicals. The bonding patterns of carbon, with its valence of four—formal single, double, and triple bonds, plus structures with delocalized electrons—make the array of organic compounds structurally diverse, and their range of applications enormous.

They form the basis of, or are constituents of, many commercial products including pharmaceuticals; petrochemicals and agrichemicals, and products made from them including lubricants, solvents; plastics; fuels and explosives. The study of organic chemistry overlaps organometallic chemistry and biochemistry, but also with medicinal chemistry, polymer chemistry, and materials science

Our activity

Preparations and aim

In our activity we would like to introduce three organic compounds:

• methanol [ CH₃OH ]
• methanediol [ CH₂(OH)₂ ]
• dimethylamine [ (CH₃)₂NH ]

We decided to explain their structures using fruits and toothsticks. The idea has been accepted on the spot by Atena and she could not wait to perform this. We used the following fruits (of course you can use different ones):

• Huckleberries for Hydrogen
• Physalis for Nitrogen
• Red grapes as Carbon
• White grapes for Oxygen

As Atena is quite familiar with reading, we suggested her to take a book where the shapes have been presented and let her figure it out. She made it perfectly.

Step 1 – Prepare the fruits as atoms

Firstly, you need to choose fruits you like and assign them to the particular atoms. We suggest to use the ball-shaped ones as it represents atoms more accurately. Assign one kind of fruit to only one atom name. Please use some letters so your kid is not confused what is what.

Step 2 – Prepare tooth-sticks

Secondly, it is pretty straight forward step, but if your kid is smaller you might break the longer tooth-sticks into shorter parts.

Step 3 – Get the template and follow it

Thirdly, once we have all the atoms, tooth-sticks and pictures ready, beginnig the play. It might be needed to perform one example together with your kid and it follows the rule. Or maybe not 🙂 Nevertheless, it has to be a great and joyful activity so support your kid if needed. After all you can eat the molecules 🙂 🙂

Step 4 – Activity extension

Encourage your kid to count the fruits in each molecule and say out-loud the number and names of the atoms building the molecules. Example below:

• “To build methanol I used one red grape, one light grape, and four huckleberries, so it means that methanol compound consists of 1 carbon atom, 1 oxygen atom and 4 hydrogen atoms”.

Great TIP: Look together with your child into the periodic table and read the basic information about a number of protons in the nucleus and number of electron shells of each atom in the compound.

This way we have finished our activity and short story about atoms and molecules. If you ignited the spark in your child’s mind, then let him/her discover more. Support him or her!

Questions and answers

Taking the opportunity, we have gathered the most popular questions and answers related to the atoms and molecules. We hope it will be your one-stop-shop in this topic.

Summary

We are curious about what are your opinions about the activity and the article. Please leave a comment.