- Chemical elements are made up of particles called atoms.
- All the atoms of the same chemical element are identical, of the same size, mass and chemical properties.
- Chemical compounds are made up of atoms of two or more different elements.
- A chemical reaction involves only the separation, combination or rearrangement of the atoms. It is never about a creation or destruction of them.
An atom is made up of two main parts: a nucleus and orbitals . These in turn are made up of particles, called subatomic particles , since they are found inside the atom. The main ones are protons, neutrons and electrons. Each chemical element is going to have a defined number of these particles in its atom. It is what differentiates them.
Protons , which are particles that carry a positive electrical charge, and neutrons , which are particles that have no charge, are located in the nucleus . All protons and neutrons are accumulated in the nucleus, compact together, so that they form a well-defined center for the atom. Due to the charges present there, the nucleus has a positive charge .
The orbitals are the paths that form when circulating particles called electrons around the nucleus of the atom. Electrons have a negative charge , which is offset by the positive charge of the nucleus. This makes the stable atoms electrically neutral particles.
As mentioned: the atom of each chemical element is going to have a certain number of subatomic particles s. For example, the Helium atom has 2 protons, 2 neutrons, and 2 electrons. No other stable chemical element is going to have 2 of each.
Atomic number and Mass number
The mass number is the number of protons and neutrons that an atom has in its nucleus. It is represented by the letter A , and it is based on it that the atomic mass of the chemical elements is determined.
Atoms in chemical compounds
Atoms are capable of grouping together to form molecules, which are the fundamental particles of new pure substances. If atoms form chemical elements, by analogy molecules form chemical compounds . Compounds can be of two types: ionic or covalent.
In an ionic compound , atoms bond with each other due to electrostatic forces caused by electrons to spare or lack of them. An example of an ionic compound is sodium chloride (NaCl), better known as table salt . These compounds, when dissolved in water, are capable of separating into their two components with electrical charges, positive and negative.
In a covalent compound , the atoms come together due to the electrons they have in their last shell. They tend to share them with the right atoms so that they both reach stability, which is achieved by having eight electrons in that shell. This requirement for chemical stability is called the Octet Rule .
1.- A Hydrogen atom has 1 proton and 1 electron.
2.- A Helium atom has 2 protons, 2 neutrons and 2 electrons.
3.- A Lithium atom has 3 protons, 3 neutrons and 3 electrons.
4.- A Beryllium atom has 4 protons, 4 neutrons and 4 electrons.
5.- A Boron atom has 5 protons, 5 neutrons and 5 electrons.
6.- A Carbon atom has 6 protons, 6 neutrons and 6 electrons.
7.- A Nitrogen atom has 7 protons, 7 neutrons and 7 electrons.
8.- An oxygen atom has 8 protons, 8 neutrons and 8 electrons.
9.- A fluorine atom has 9 protons, 9 neutrons and 9 electrons.
10.- A Neon atom has 10 protons, 10 neutrons and 10 electrons.
11.- A sodium atom has 11 protons, 11 neutrons and 11 electrons.
12.- A Magnesium atom has 12 protons, 12 neutrons and 12 electrons.
13.- An aluminum atom has 13 protons, 13 neutrons and 13 electrons.
14.- A Silicon atom has 14 protons, 14 neutrons and 14 electrons.
15.- A Phosphorus atom has 15 protons, 15 neutrons and 15 electrons.
16. A sulfur atom has 16 protons, 16 neutrons and 16 electrons.
17.- A chlorine atom has 17 protons, 17 neutrons and 17 electrons.
18.- An Argon atom has 18 protons, 18 neutrons and 18 electrons.
19.- A Potassium atom has 19 protons, 19 neutrons and 19 electrons.
20.- A Calcium atom has 20 protons, 20 neutrons and 20 electrons.
21.- A Scandium atom has 21 protons, 21 neutrons and 21 electrons.
22.- A Titanium atom has 22 protons, 22 neutrons and 22 electrons.
23.- A Vanadium atom has 23 protons, 23 neutrons and 23 electrons.
24.- A Chromium atom has 24 protons, 24 neutrons and 24 electrons.
25.- A Manganese atom has 25 protons, 25 neutrons and 25 electrons.
26.- An iron atom has 26 protons, 26 neutrons and 26 electrons.
27.- A Cobalt atom has 27 protons, 27 neutrons and 27 electrons.
28.- A Nickel atom has 28 protons, 28 neutrons and 28 electrons.
29.- A Copper atom has 29 protons, 29 neutrons and 29 electrons.
30.- A Zinc atom has 30 protons, 30 neutrons and 30 electrons.
31.- A Gallium atom has 31 protons, 31 neutrons and 31 electrons.
32.- A Germanium atom has 32 protons, 32 neutrons and 32 electrons.
33.- An Arsenic atom has 33 protons, 33 neutrons and 33 electrons.
34.- A selenium atom has 34 protons, 34 neutrons and 34 electrons.
35.- A Bromine atom has 35 protons, 35 neutrons and 35 electrons.
36.- A Krypton atom has 36 protons, 36 neutrons and 36 electrons.
37.- A Rubidium atom has 37 protons, 37 neutrons and 37 electrons.
38.- A Strontium atom has 38 protons, 38 neutrons and 38 electrons.
39.- An atom of Yttrium has 39 protons, 39 neutrons and 39 electrons.
40.- A zirconium atom has 40 protons, 40 neutrons and 40 electrons.
41.- A Niobium atom has 41 protons, 41 neutrons and 41 electrons.
42.- A Molybdenum atom has 42 protons, 42 neutrons and 42 electrons.
43.- A Technetium atom has 43 protons, 43 neutrons and 43 electrons.
44.- A ruthenium atom has 44 protons, 44 neutrons and 44 electrons.
45.- A Rhodium atom has 45 protons, 45 neutrons and 45 electrons.
46.- A Palladium atom has 46 protons, 46 neutrons and 46 electrons.
47.- A Silver atom has 47 protons, 47 neutrons and 47 electrons.
48.- A Cadmium atom has 48 protons, 48 neutrons and 48 electrons.
49.- An atom of Indium has 49 protons, 49 neutrons and 49 electrons.
50.- A Tin atom has 50 protons, 50 neutrons and 50 electrons.