Hydrogen is the most abundant element in the universe and make up 75% of the mass of the universe.
The next most abundant element in the universe is Helium.
They are the 2 simplest elements (by atomic structure) that exists. Helium is also produced by stars like our sun that fuses 4H atoms into 1 He atom. The loss in mass when this takes place is converted into energy based on Einstein fomula of E = m (c squared)
The lightest element and the second lightest element in the universe are hydrogen (H) and helium (He)
Why are they so light can be explained by looking at their atomic structure.
Atoms of all elements are made up of protons, neutrons and electrons. Protons and neutrons have an atomic mass of 1. The difference between protons and neutrons is that protons have a positive charge whereas neutrons are not charged. Protons and neutrons make up nucleas of atoms.
Electrons are negatively charged and are very small having almost no mass compared to protons and neutrons. Electrons orbit around the nucleas of atoms.
An atom of oxygen contain 8 protons and 8 neutrons at its nucleas and has 8 electrons in orbit. It has an atomic mass of 16 from its protons & neutrons.
A Hydrogen atom H has only 1 proton & 1 electron giving it an atomic mass of 1.
The typical He atom has 2 protons, 2 neutrons, and 2 electrons giving it an atomic mass of 4 (there is a very rare isotope of He with only 1 neutron)
Electrons like to be in pairs so a single H atom is not stable. Each H atom bonds with another H atom so that they can share their electron. So hydrogen exists as molecules of H2 (2 H atoms bonded together)
The 2 electrons of He is already in a stable pair that completely fill the first orbital level (shell). So He molecules is just a single He atom. Because its orbital shell is completely filled He is an inert element that does not react with other elements.
Because of its inertness and its light weight, it is ideal for filling balloons or airships.
H atoms have only 1 electron and achieves a measure of stability by sharing electrons with another H atom. Hydrogen is far less stable than He. The H2 molecule can split to allow H atoms to combine with other elements.
For example mixing hydrogen gas with oxygen gas is dangerous as the mixture will burn explosively to form molecules of H2O that has very strong bonds.
Stars like our sun is mainly made up of hydrogen and fuses hydrogen into helium atoms.
The solar system with its planets orbiting the sun on different planes is like a giant atom.
The electrons of atoms orbit around their nucleas in shells like the planets have seperate orbits.
The orbits of planets are not all on the same plane. The orbits of electrons also have different orbitals: s, p, d, f orbitals
The planets orbit around the sun in accordance to physical laws such as the law of gravity. Electrons also orbit nucleas according to laws.
It has already been mentioned that electron like to be in pairs.
The shells of the orbits of electrons is like the different orbits of planets at different distances from the sun.
Electrons like to fill up its shells. He with 2 electrons that fills up the its first shell is very stable and is an inert gas.
Oxygen is an element that often combines with other elements. This is because of the orbitals of its electrons is not stable.
It has 8 electrons. 2 of these completely filled the first shell. The remaining 6 orbits as 3 pairs in the 2nd shell.
In order to be stable, an O atom has to either lose all the 6 electrons in the 2nd shell or to fill the 2nd shell by acquiring 2 electrons to make an octet of 4 pairs.
Getting 2 is off course easier than giving up 6. Just like how H atoms gain stability by sharing electrons to form H2 molecules, O atoms will share electrons to form O2 molecules of 2 O atoms. The rare form of oxygen as O3 molecules is beyond the scope of this post.
As we go on to the 3rd shell and later shells for large atoms with a lot of electrons, it is very difficult to completely fill the capacity of its outermost shell. So atoms are stable by filling an octet of 4 pairs in its outermost shell.
There is a strange completeness in the number 8 or 2 cube (2x2x2). In computers a byte of information is made up of 8 bits. Each bit is one of the Binary state of 1 or 0. Computer language is based on binary states. Electrons like to be in pairs.
Is it all coincidence that everything seems to follow some hidden laws?
The planets orbit around the sun because of gravity. Most of the mass of the Solar system is in the sun.
Most of the mass of atoms is in its nucleas which exerts its gravity on the electrons.
The H nucleas is the nucleas that has the smallest mass of all elements. Just 1 proton without any neutron. Is the low gravity of this tiny mass one of the reasons why H atoms easily lose its electron and is so reactive?
Hydrogen is the lightest gas and will provide balloons and airships with the greatest lift. Why is hydrogen not used to fill these?
The Carbon in fossil fuels form CO2 which causes the greenhouse effect for climate change.
The burning of H2 produces H20 ( water which is a desirable product) instead of CO2. Why is H2 not widely used as a clean fuel?
Besides the possibility of using H2 as a fuel for combustion will fusing H2 to form He become a very important source of energy?
The simplicity and smallness of both H2 and He may be why they are the easiest elements to be formed in a Big Bang. Is this why they are the 2 most common elements in the universe?
Hydrogen and Helium are the most common elements in the universe. Hydrogen is also produced by green algae in ocean water using sunlight to break up H20 molecules. Why is both H2 and He so rare on earth?
Is hydrogen really rare as alleged or is there a lot of hydrogen on earth?
I will not give the answers to the above untill readers have tried to answer the questions 🦋