جميع المواضيع المتعلقة بـ ‘electron’

 

Electron affinity

Electron affinity

It is the amount of energy given out when an electron is added to a neutral gaseous atom. This results in the formation of an anion.

For example Cl + e– → Cl + energy. The electron affinity of chlorine is 348 kJ mol-1.

Electron affinity changes across a period. The electron affinity of the atoms increases from left to right along a period…

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Characteristics of periods and groups of a periodic table

Characteristics of periods and groups of a periodic table

Characteristics of periods

1 –  Valence electrons. On moving from left to right in a period, the number of valence electrons increases from 1 to 8 (except first period where the increase is from one to two only).

  Na         Mg         Al          Si            P           S           Cl          Ar

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De Broglie’s theory of wave nature of electrons

De Broglie’s theory of wave nature of electrons: Electron, like light has dual character (particle and wave like) de Broglie suggested the wave nature of electrons and derived the relation λ = h/p where λ is the wavelength and p the momentum of the electron and h is Plank’s constant. This relation is verified by interference and  diffraction experiments with electrons.

Heisenberg’s uncertainty principle: It is impossible to…

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The Periodic Table

Elements can be grouped into classes according to the chemical compounds they form. If the elements are written in a table in order of increasing atomic weights, they fall naturally into a series of columns, with members of a given chemical group in the same column. This is called the periodic table of the elements.The term periodic means recurring at regular intervals. The original periodic tables were…

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Structure of the Atom

Each atom is made up of an inner core called the nucleus.

 – Most of the atom’s mass is located in the relatively small nucleus.

 – The rest of the atom is comprised of a relatively large region outside the nucleus where the electrons are found.

– The atom is made of 3 subatomic particles:

Positively charged protons Neutral particles called neutrons Negatively charged electrons

– Protons and neutrons…

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Atomic Theory

Dalton’s Model of the atom. It is the basis of our understanding of the nature of matter. The following four statements comprise Dalton’s Model:

a –  All matter is made up of extremely tiny. particles. called atoms.

b-  Atoms are indivisible.

c – Atoms of the same element are alike.

d –  Atoms of different elements are different.

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