2. The atomic structure of an element
refers to the constitution of its
nucleus and the arrangement of the
electrons around it. Primarily, the
atomic structure of matter is made
up of protons, electrons and
neutrons.
2
4. PODTULATES AND CAUSES OF FALIURE
POSTULATES
All matter is made up of tiny, indivisible particles called atoms.
All atoms of a specific element are identical in mass, size, and
other properties. However, atoms of different element exhibit
different properties and vary in mass and size.
Atoms can neither be created nor destroyed. Furthermore, atoms
cannot be divided into smaller particles.
Atoms of different elements can combine with each other in fixed
whole-number ratios in order to form compounds.
Atoms can be rearranged, combined, or separated in chemical
reactions.
It does not account for
subatomic particles.
It does not account for isotopes.
It does not account for Isobars.
Elements need not combine in
simple, whole-number ratios to
form compounds.
It does not account for
alltropes.
4
CAUSES OF FALIURE
7. PODTULATES AND CAUSES OF FALIURE
POSTULATES
An atom consists of a positively
charged sphere and the electrons are
embedded in it.
The negative and positive charges
are equal in magnitude. From the
above two one can say that the atom
as a whole is electrically neutral.
Thomson model of an atom could not
explain the stability of an atom, i.e.,
how a positive charge in the atom
holds the negatively charged electrons.
It could not explain the position of
the nucleus in an atom and the
scattering of alpha particles. 7
CAUSES OF FALIURE
10. PODTULATES AND CAUSES OF FALIURE
POSTULATES
The mass of an atom is concentrated
in a small space called the nucleus.
Atoms majorly consist of positively
charged particles.
Negatively charged electrons revolve
around atoms in circular paths called
orbits at very high speed.
An atom is electrically neutral i.e. has
no net charge.
According to him, charged electrons revolve
around atom in circular paths so it should
experience acceleration due to which it should
lose energy continuously in the form of
electromagnetic radiations and then eventually
fall into the nucleus there by making the atom
unstable.Rutherford’s model of an atom could
not explain as to how the electrons are
arranged in the orbits around the nucleus.
CAUSES OF FALIURE
13. PODTULATES AND CAUSES OF FALIURE
POSTULATES
• In an atom, electrons (negatively charged) revolve around the positively charged
nucleus in a definite circular path called orbits or shells.
• Each orbit or shell has a fixed energy and these circular orbits are known as
orbital shells.
• The energy levels are represented by an integer (n=1, 2, 3…) known as
the quantum number. This range of quantum number starts from nucleus side
with n=1 having the lowest energy level. The orbits n=1, 2, 3, 4… are
assigned as K, L, M, N…. shells and when an electron attains the lowest energy
level, it is said to be in the ground state.
• The electrons in an atom move from a lower energy level to a higher energy level
by gaining the required energy and an electron moves from a higher energy level
to lower energy level by losing energy.
• Bohr’s model of an atom failed
to explain the Zeeman Effect
(effect of magnetic field on the
spectra of atoms).
• It also failed to explain the
Stark effect (effect of electric
field on the spectra of atoms).
• It violates the Heisenberg
Uncertainty Principle.
• It could not explain the spectra
obtained from larger atoms
13
CAUSES OF FALIURE
16. POSTULATES
• The energy of an electron is quantized i.e. an electron can only have certain specific values of energy.
• The quantized energy of an electron is the allowed solution of the Schrödinger wave equation and it is the result of wave like
properties of electron.
• As per Heisenberg’s Uncertainty principle, the exact position and momentum of an electron cannot be determined. So the
only probability of finding an electron at a position can be determined and it is |ψ|2 at that point where ψ represents the
wave-function of that electron.
• An atomic orbital is the wave-function (ψ) of an electron in an atom. Whenever an electron is described by a wave-function, it
occupies atomic orbital. As an electron can have many wave-functions, there are many atomic orbitals for the electron. Every
wave-function or atomic orbital have some shape and energy associated with it. All the information about the electron in an
atom is stored in its orbital wave function ψ and quantum mechanics makes it possible to extract this information out of ψ.
• The probability of finding an electron at a point within an atom is proportional to the square of the orbital wave function i.e.,
| ψ |2 at that point. | ψ |2 is known as probability density and is always positive.
16
18. 18
Electron configurations describe where electrons are located around the
nucleus of an atom.
Ex: The electron configuration of lithium, 1s²2s¹, tells us that lithium
has two electrons in the 1s subshell and one electron in the 2s subshell.
22. 22
Element Atomic Number Element Symbol Element Name Element Electron Configuration
1 H Hydrogen 1s1
2 He Helium 1s2
3 Li Lithium [He] 2s1
4 Be Beryllium [He] 2s2
5 B Boron [He] 2s2 2p1
6 C Carbon [He] 2s2 2p2
7 N Nitrogen [He] 2s2 2p3
8 O Oxygen [He] 2s2 2p4
9 F Fluorine [He] 2s2 2p5
10 Ne Neon [He] 2s2 2p6
11 Na Sodium [Ne] 3s1
12 Mg Magnesium [Ne] 3s2
13 Al Aluminium [Ne] 3s2 3p1
14 Si Silicon [Ne] 3s2 3p2
15 P Phosphorus [Ne] 3s2 3p3
23. 23
Element Atomic Number Element Symbol Element Name Element Electron Configuration
16 S Sulfur [Ne] 3s2 3p4
17 Cl Chlorine [Ne] 3s2 3p5
18 Ar Argon [Ne] 3s2 3p6
19 K Potassium [Ar] 4s1
20 Ca Calcium [Ar] 4s2
21 Sc Scandium [Ar] 3d1 4s2
22 Ti Titanium [Ar] 3d2 4s2
23 V Vanadium [Ar] 3d3 4s2
24 Cr Chromium [Ar] 3d5 4s1
25 Mn Manganese [Ar] 3d5 4s2
26 Fe Iron [Ar] 3d6 4s2
27 Co Cobalt [Ar] 3d7 4s2
28 Ni Nickel [Ar] 3d8 4s2
29 Cu Copper [Ar] 3d10 4s1
30 Zn Zinc [Ar] 3d10 4s2
24. 24
Element Atomic Number Element Symbol Element Name Element Electron Configuration
31 Ga Gallium [Ar] 3d10 4s2 4p1
32 Ge Germanium [Ar] 3d10 4s2 4p2
33 As Arsenic [Ar] 3d10 4s2 4p3
34 Se Selenium [Ar] 3d10 4s2 4p4
35 Br Bromine [Ar] 3d10 4s2 4p5
36 Kr Krypton [Ar] 3d10 4s2 4p6
37 Rb Rubidium [Kr] 5s1
38 Sr Strontium [Kr] 5s2
39 Y Yttrium [Kr] 4d1 5s2
40 Zr Zirconium [Kr] 4d2 5s2
41 Nb Niobium [Kr] 4d4 5s1
42 Mo Molybdenum [Kr] 4d5 5s1
43 Tc Technetium [Kr] 4d5 5s2
44 Ru Ruthenium [Kr] 4d7 5s1
45 Rh Rhodium [Kr] 4d8 5s1
25. 25
Element Atomic Number Element Symbol Element Name Element Electron Configuration
46 Pd Palladium [Kr] 4d10
47 Ag Silver [Kr] 4d10 5s1
48 Cd Cadmium [Kr] 4d10 5s2
49 In Indium [Kr] 4d10 5s2 5p1
50 Sn Tin [Kr] 4d10 5s2 5p2
51 Sb Antimony [Kr] 4d10 5s2 5p3
52 Te Tellurium [Kr] 4d10 5s2 5p4
53 I Iodine [Kr] 4d10 5s2 5p5
54 Xe Xenon [Kr] 4d10 5s2 5p6
55 Cs Cesium [Xe] 6s1
56 Ba Barium [Xe] 6s2
57 La Lanthanum [Xe] 5d1 6s2
58 Ce Cerium [Xe] 4f1 5d1 6s2
59 Pr Praseodymium [Xe] 4f3 6s2
60 Nd Neodymium [Xe] 4f4 6s2
26. 26
Element Atomic Number Element Symbol Element Name Element Electron Configuration
61 Pm Promethium [Xe] 4f5 6s2
62 Sm Samarium [Xe] 4f6 6s2
63 Eu Europium [Xe] 4f7 6s2
64 Gd Gadolinium [Xe] 4f7 5d1 6s2
65 Tb Terbium [Xe] 4f9 6s2
66 Dy Dysprosium [Xe] 4f10 6s2
67 Ho Holmium [Xe] 4f11 6s2
68 Er Erbium [Xe] 4f12 6s2
69 Tm Thulium [Xe] 4f13 6s2
70 Yb Ytterbium [Xe] 4f14 6s2
71 Lu Lutetium [Xe] 4f14 5d1 6s2
72 Hf Hafnium [Xe] 4f14 5d2 6s2
73 Ta Tantalum [Xe] 4f14 5d3 6s2
74 W Tungsten [Xe] 4f14 5d4 6s2
75 Re Rhenium [Xe] 4f14 5d5 6s2
27. 27
Element Atomic Number Element Symbol Element Name Element Electron Configuration
76 Os Osmium [Xe] 4f14 5d6 6s2
77 Ir Iridium [Xe] 4f14 5d7 6s2
78 Pt Platinum [Xe] 4f14 5d9 6s1
79 Au Gold [Xe] 4f14 5d10 6s1
80 Hg Mercury [Xe] 4f14 5d10 6s2
81 Tl Thallium [Xe] 4f14 5d10 6s2 6p1
82 Pb Lead [Xe] 4f14 5d10 6s2 6p2
83 Bi Bismuth [Xe] 4f14 5d10 6s2 6p3
84 Po Polonium [Xe] 4f14 5d10 6s2 6p4
85 At Astatine [Xe] 4f14 5d10 6s2 6p5
86 Rn Radon [Xe] 4f14 5d10 6s2 6p6
87 Fr Francium [Rn] 7s1
88 Ra Radium [Rn] 7s2
89 Ac Actinium [Rn] 6d1 7s2
90 Th Thorium [Rn] 6d2 7s2
28. 28
Element Atomic Number Element Symbol Element Name Element Electron Configuration
91 Pa Protactinium [Rn] 5f2 6d1 7s2
92 U Uranium [Rn] 5f3 6d1 7s2
93 Np Neptunium [Rn] 5f4 6d1 7s2
94 Pu Plutonium [Rn] 5f6 7s2
95 Am Americium [Rn] 5f7 7s2
96 Cm Curium [Rn] 5f7 6d1 7s2
97 Bk Berkelium [Rn] 5f9 7s2
98 Cf Californium [Rn] 5f10 7s2
99 Es Einsteinium [Rn] 5f11 7s2
100 Fm Fermium [Rn] 5f12 7s2
101 Md Mendelevium [Rn] 5f13 7s2
102 No Nobelium [Rn] 5f14 7s2
103 Lr Lawrencium [Rn] 5f14 7s2 7p1
104 Rf Rutherfordium [Rn] 5f14 6d2 7s2
105 Db Dubnium [Rn] 5f14 6d3 7s2
