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 numberElementSymbolsElectron configurationElectron structure
3LithiumLiIS2 2S12.1
4BerylliumBeIS2 2S22,2
5BoronBIS2 2S2 2P12,3
6CarbonCIS2 2S2 2P22,4
7NitrogenNIS2 2S2 2P32,5
8OxygenOIS2 2S2 2P42,6
9FlourineFIS2 2S2 2P52,7
10NeonNeIS2 2S2 2P62,8
11SodiumNaIS2 2S2 2P6 3S12,8,1
12MagnesiumMgIS2 2S2 2P6 3S22,8,2
13AluminiumAlIS2 2S2 2P6 3S2 3P12,8,3
14SiliconSiIS2 2S2 2P6 3S2 3P22,8,4
15PhosphorusPIS2 2S2 2P6 3S2 3P32,8,5
16SulphurSIS2 2S2 2P6 3S2 3P42,8,6
17ChlorineClIS2 2S2 2P6 3S2 3P52,8,7
18ArgonArIS2 2S2 2P6 3S2 3P62,8,8
19PotassiumKIS2 2S2 2P6 3S2 3P6 4S12,8,8,1
20CalciumCaIS2 2S2 2P6 3S2 3P6 4S22,8,8,2

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

ElementLatin nameSymbol

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/ionProtons numberNeutron numberElectron numberMass number

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/ionProton numberElectron numberNeutron numberMass no
   X19 A1837

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 particlesRelative massRelative charge

Summary of the discoveries of atomic sub particles and other important discoveries

1John DaltonBilliard ball atomic structure
2Joseph John ThomsonElectron
3Ernest RutherfordProton and Nucleus
4Niels BohrEnergy levels/shells/orbits
5James ChadwickNeutron
6Erwin SchrodingerElectron cloud
7R.A MillikanCharge o an electron
8Dmitriv MendeleevPeriodic table
9Goldsten and Julius PluckerCathode rays  
10Henry MoseleyAtomic number

Analysing atomic structure is quite an important aspect of Chemistry and veryn vital in Olevel Chemistry and exams.

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