How to Deduce the Atomic Structure of the First 20 Elements
Atomic structure is a very important topic in Chemistry and i want to show you how to Deduce the Atomic Structure of the First 20 Elements
The atomic structures of the first 20 elements are very easy to deduce and it is important to note that we can easily configure the structure of the atoms by first recalling the atomic numbers of the elements.
For example, if we pick sodium which has atomic number 11, the electron or atomic structure is 2, 8, 1.
Summary of the Atomic Structure of the First 20 Elements
Atomic number | Element | Symbols | Electron configuration | Electron structure |
1 | Hydrogen | H | 1S1 | 1 |
2 | Helium | He | IS2 | 2 |
3 | Lithium | Li | IS2 2S1 | 2.1 |
4 | Beryllium | Be | IS2 2S2 | 2,2 |
5 | Boron | B | IS2 2S2 2P1 | 2,3 |
6 | Carbon | C | IS2 2S2 2P2 | 2,4 |
7 | Nitrogen | N | IS2 2S2 2P3 | 2,5 |
8 | Oxygen | O | IS2 2S2 2P4 | 2,6 |
9 | Flourine | F | IS2 2S2 2P5 | 2,7 |
10 | Neon | Ne | IS2 2S2 2P6 | 2,8 |
11 | Sodium | Na | IS2 2S2 2P6 3S1 | 2,8,1 |
12 | Magnesium | Mg | IS2 2S2 2P6 3S2 | 2,8,2 |
13 | Aluminium | Al | IS2 2S2 2P6 3S2 3P1 | 2,8,3 |
14 | Silicon | Si | IS2 2S2 2P6 3S2 3P2 | 2,8,4 |
15 | Phosphorus | P | IS2 2S2 2P6 3S2 3P3 | 2,8,5 |
16 | Sulphur | S | IS2 2S2 2P6 3S2 3P4 | 2,8,6 |
17 | Chlorine | Cl | IS2 2S2 2P6 3S2 3P5 | 2,8,7 |
18 | Argon | Ar | IS2 2S2 2P6 3S2 3P6 | 2,8,8 |
19 | Potassium | K | IS2 2S2 2P6 3S2 3P6 4S1 | 2,8,8,1 |
20 | Calcium | Ca | IS2 2S2 2P6 3S2 3P6 4S2 | 2,8,8,2 |
If you notice, the symbols of sodium, potassium differ from others; as a matter of fact the symbols are not actually gotten from the letters of the name of the elements.
So, how do these symbols of the elements originate?
These symbols are gotten from the Latin names of the elements, and I want to show you lst of other elements, their Latin names, and their symbols.
A complete list of elements with their Latin names
Element | Latin name | Symbol |
Sodium | Natrium | Na |
Potassium | Karim | K |
Silver | Argentum | Ag |
Gold | Aurium | Au |
Mercury | Argentum | Hg |
Tin | Stannum | Sn |
Arrangement of subatomic particles in an atom
The modern structure of the atom is composed of protons and neutrons that are located in the nucleus of the atom while the electrons revolve around the nucleus in elliptical orbits.
The sum of protons and neutrons are collectively called nucleons or mass numbers.
Mathematically, mass number = protons + neutrons
Also, take note that the number of protons= atomic number
If an atom is neutral, then the number of protons and electrons balanced out however if the atom is charged ( an ion) then the number of protons and electrons are not the same.
For a positive ion(cation), the number of electrons will be lower than the number of protons since the atom lost electrons but if the atom is negatively charged (anion) then the number of electrons will be higher than the number of protons because the atom gained electrons.
Moreso, net charge is equal to protons minus electrons (net charge = protons –electron)
To buttress this concept, I will show some solved analysis on the deductions of the arrangement of subatomic particles in an atom.
Analysis 1 on atomic structure
Atom/ion | Protons number | Neutron number | Electron number | Mass number |
Na | 11 | 12 | 11 | 23 |
O | 8 | 9 | 8 | 17 |
Ca | 20 | 20 | 20 | 40 |
Mg2+ | 12 | 13 | 10 | 25 |
Cl– | 17 | 18 | 18 | 35 |
Hint: The isotopes of the elements were used in the analysis table just to demonstrate the concept we have been discussing.
Did you notice that the magnesium and chloride ions have different numbers of electrons and protons?
For the magnesium ion, it is +2 positively charged because the proton number is 12 while the number of the electrons is 10, 12-10 = +2
Also for the chloride ion, the number of electrons increased by 1 because the atom gained one electron.
Analysis 2 on Atomic structure
Atom/ion | Proton number | Electron number | Neutron number | Mass no |
X | 19 | A | 18 | 37 |
Y3+ | C | 10 | 14 | 27 |
Z2- | 16 | 18 | D | 33 |
To deduce the following missing subatomic particles values, you need to pay attention to the exact formula needed.
A = Electron number: since it is a neutral atom, the proton number should be equal to the electron number. Therefore electron number is 19.
C=Proton number: Mass number – neutron number (27 -10 =13)
D= Neutron number is mass number – proton number (33-16 =17)
Important facts about subatomic particles
Sub particles | Relative mass | Relative charge | |
1 | Proton | 1 | +1 |
2 | Electron | 1/1840 | -1 |
3 | Neutron | 1 | Nil |
Summary of the discoveries of atomic sub particles and other important discoveries
Scientists | Discoveries | |
1 | John Dalton | Billiard ball atomic structure |
2 | Joseph John Thomson | Electron |
3 | Ernest Rutherford | Proton and Nucleus |
4 | Niels Bohr | Energy levels/shells/orbits |
5 | James Chadwick | Neutron |
6 | Erwin Schrodinger | Electron cloud |
7 | R.A Millikan | Charge o an electron |
8 | Dmitriv Mendeleev | Periodic table |
9 | Goldsten and Julius Plucker | Cathode rays |
10 | Henry Moseley | Atomic number |
Analysing atomic structure is quite an important aspect of Chemistry and veryn vital in Olevel Chemistry and exams.