Already in antiquity around 450 BC. philosophers like Democritus assumed that our world is made up of the smallest particles. They named these atoms, which is Greek for «indivisible». As the first atoms were discovered, we named them after the models of the Greek philosophers.
But today we know that the atoms are by no means indivisible, but are made up of a large number of even smaller particles, the so-called cottage cheeseput together.
Quark’s atom – basic knowledge
The structure of an atom consists of a nucleus and a atomic shell. If you want to deepen your knowledge about the structure of the atom, we also have a separate article for that.
The atomic nucleus
The nucleus consists of positively charged protons and neutrally charged neutrons.These are made by the strong nuclear power held together. The nucleus makes up 99.9% of the total atom’s mass, although it is very small compared to the atomic shell.
Comparison of the size ratio between atomic shell and atomic nucleus: If an atom were to grow to the size of a soccer field, the nucleus would always be the size of a grain of rice in the middle of the field.
The number of protons P in an atomic nucleus is caused by the atomic number Z specified.
For example, hydrogen has the atomic number Z = 1, so its nucleus consists of one proton. The number of protons in the nucleus determines the element. For example, if you increased the number of protons to two, you would get the element helium.
This happens, for example, with nuclear fusion. This process takes place, for example, inside the sun, where two lighter atomic nuclei fuse under high pressure and intense heat to form the heavier atomic nucleus of a new element.
The number of neutrons N you get by from the Mass number A the atomic number Z deduct. The mass number gives the number of all nuclear particles (protons and neutrons). The number of neutrons in an element can vary, which is what you call a isotope of the element.
So with the following formula you get the Neutron number N:
In the following we show you an example of what a task for calculating the number of neutrons in an element could look like:
task
Let’s look at this for the element sodium (Na):
The element sodium has the mass number A = 23
and the atomic number Z = 11. Its proton number corresponds to the atomic number, so sodium has 11 protons.
solution
We calculate the number of neutrons using the formula:
N=A-Z
N = 23 – 11
N = 12Natrium therefore has 12 neutrons.
The atomic nucleus consists of positively charged protons and neutral neutrons, and the atomic shell is still around the nucleus.
atomic shell
In the atomic shell are the electrons. They are negative charged and their number corresponds to the number of protons. Correspondingly, atoms are outward total neutral loaded.
However, there are so-called «ions». These are atoms or molecules with a positive or negative Charge. This charge is created when an atom gains or loses electrons. As a result, the charges of electrons and protons no longer balance each other out.
An atom with excess electrons (more electrons than protons) is negatively charged. Conversely, an atom with a lack of electrons (fewer electrons than protons) is positively charged overall.
In Bohr’s atomic model, the electrons are in different shells around the nucleus, similar to the planets in our solar system around our central star.
The electrons revolve around the positively charged nucleus in the center on fixed orbits.
Figure 1: Bohr model of the atom
elementary particles
So atoms are divisible, they are made up of protons, neutrons and electrons. But it can be even smaller. Now we come to the realm of elementary particles.
Elementary particles are the smallest known building blocks of matter. You can find them in the Standard Model of particles. They include, for example electrons, cottage cheese, photons and the Higgs boson.
While the electron is an elementary particle, protons and neutrons are not. This is because they themselves are made up of smaller particles called quarks.
Quarks belong to the group of elementary particles. They interact with each other, thereby forming new composite particles. These new particles become hadrons also called protons and neutrons. Quarks are also known as matter particles because all known matter consists of them.
types of curds
There are six types of quarks, these are also called «Flavors» (English for varieties). Their physical symbol is their initial letter, which is given here in brackets:
- The Up – Quark (u)
- The Down – Quark (d)
- The top – cottage cheese