General Awareness
preparation series
Hello readers, I am sure you all must be busy preparing for SBI PO PRELIMS and SSC CGL 2015 TIER-1.As mentioned in our earlier posts, each day
some important topic from general awareness section would be taken up for its
understanding of theory from exam point of view. In continuation of that series,
let us study general science today which is very important section in SSC CGL 2015 exam.
Today’s topic of
discussion is from Chemistry (FOR SSC CGL 2015 TIER -1)
ATOMIC STRUCTURE
Nucleons: sub
atomic particles in the nucleus of atom i.e. proton and neutrons.
Isotopes: atoms
of an element with the same atomic number but different mass number.
Mass number: Sum
of the number of protons and neutrons i.e. the total number of nucleons.
Atomic number: The
number of protons in the nucleus of an atom. This when subtracted from mass
number, gives the number of neutrons.
Isobars: atoms
having the same mass number but different atomic numbers.
Isotones: atoms
having the same number of neutrons but different umber of protons or mass
number.
Iso-electronic
species: Atoms, molecules or ions having the same number of electrons.
Quantum numbers:
The term quantum number is used to label the various energy levels or orbits
Principal quantum
number: It represents a group of shells (n)
Subsidiary quantum
number: It represents the subsidiary orbits within a shell. (l)
Magnetic quantum
number: Observed magnetism is determined by this number. (m)
Spin quantum umber:
It can have only two values positive or negative ½. (s)
Pauli’s exclusion
principle: According to this principle, an orbital can contain a maximum of
two electrons and these two electrons must be of opposite spin.
Aufbau Principle:
This principle states that in the ground state of an atom, the orbital with a
lower energy is filled up before the orbital with a higher energy
Hund’s rule of
maximum multiplicity: This rule states that the electron pairing in
orbitals of same energy will not take place unless all the available orbitals
of a given subshell contain one single electron.
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the comment section.
