Elements dont only discovered but also synthesize

1. Lesson 3:

5. Lithium
Alpha Particle
Hydrogen
Beta Particle

6. Number of neutrons
Atomic number
Mass number
Number of magnesium
atom

7. ISOTOPE NOTATION
Atomic
Number/
Total no. of
Protons
Mass Number/ Total
no. of Protons and
Neutrons

8. Alpha Decay
Beta Decay
Positron Emission
Electron Capture

10. Neutron capture by nucleus
followed by beta decay
Direct addition of protons to
the nucleus
Direct addition of a nuclear
projectile that contains one or
more protons
Mixing chemicals to form
new elements

11. The Discovery of ATOM and the
concept of Atomic Number

13. • In 1897, JJ Thompson was working on cathode ray tubes.
• In his experiments he discovered the presence of a negatively
charge particle inside an atom. He called them “CORPUSCLES” but
now we call them “ELECTRONS”. He thought that this negatively
charge particles were embedded in a positively charge atom.

14. •This was proven wrong when
in 1911 Ernest Rutherford did
the GOLD FOIL EXPERIMENT.
He took a very thin gold foil
and bombarded it with alpha
particles he then surrounded
it with a screen that could
detect alpha particles.

15. Conclusions of Rutherford’s Gold foil
Experiment:
•Most of the
atom is
empty space.
•He also
observed that
some of the
alpha particles
were deflected
side ways and
some bounce
back.

16. Conclusions of Rutherford’s Gold foil
Experiment:
•He concluded that
the positive charge
is concentrated at
the center while
the negative
charge orbit
around it like how
planets orbit
around the sun.
That is how he
discovered the
NUCLEUS.

17. • Back then, they imagine the atom to have a positively charge
nucleus with electron orbiting around it.
• Soon Ernest Rutherford discovered that the nucleus of an atom
is made up of positively charge subatomic particles called
PROTONS.

18. •In 1932, James Chadwick (who
was a student of Ernest
Rutherford) did an experiment
with alpha particles and
beryllium atom.
• He fired beryllium with alpha
particle. A form of radiation
was produced. He observed
that this was the same mass as
proton but has no charge. He
later called these NEUTRONS.

19. Atomic Mass or
Mass Number –
total of Proton &
Neutron in an
element.

21. The Missing Link: The Holy Grail of Synthetic
Elements

22. How are the elements in the periodic table
organized in each period?
•Sir Henry Moseley
discovered that the
properties of the elements
vary periodically with the
atomic number, and not
with the atomic weight
previously accepted under
Mendeleev’s atomic mass
principle.

23. • With the use of x-ray
spectroscopy, he was able to
determine the atomic
number of an element.
• In the process, a beam of
electrons is bombarded
causing x-ray spectral lines to
come out of the elements. His
quantitative results proved
that the frequency of the x-
rays given off by an element
is directly related to the
position of the element in
the periodic table.

24. Atomic Number
– refers to the
number of proton
in an element.

26. How Are Elements Synthesize In The
Laboratory?

27. 92
U
Uranium

28. • In 1937, two Italian scientist Carlo Perrier &
Emilio Segre discovered the element 43.
• Greek word “Tekhnetos” means “artificial”.
43
Tc
Technicium

29. • They bombarded deuteron (isotope of hydrogen
with 1 proton and 1 neutron) by Molybdenum.
• When this deuteron hits molybdenum its proton
is attached in the nucleus and neutrons are
emitted. The addition of 1 proton resulted into
element 43 or “Technicium”.
• They bombarded deuteron (isotope of hydrogen
with 1 proton and 1 neutron) by Molybdenum.
• When this deuteron hits molybdenum its proton
is attached in the nucleus and neutrons are
emitted. The addition of 1 proton resulted into
element 43 or “Technicium”.
=
Deuteron Molybdenum
“Technicium”
+

30. 1
2
𝐻 + 42
97
𝑀𝑜 → 20
1
𝑛 + 43
97
𝑇𝑐
Nuclear Reaction on the creation of element
“TECHNICIUM”
Combination of deuteron
and molybdenum
• no. of protons
• no. of neutrons
• Mass no.
Mass number
(proton +
neutron)
Atomic number
(no. proton)

31. •In 1940, Dale R. Corson, Kenneth Ross
McKenzie & Emilio Segre discovered
the element 85.
85
At
Astatine
•They used cyclotron to collide alpha
particle with bismuth.

32. •A cyclotron is a circular machine that accelerates
particle or nuclei to collide them with other nuclei.
• The cyclotron makes sure that the particles are moving
fast enough to overcome electrostatic repulsion
between atoms.

33. 83
209
𝐵𝑖 + 2
4
𝐻𝑒 → 85
211
𝐴𝑡 + 20
1
𝑛
Nuclear Reaction on the creation of element
“ASTATINE”
=
𝛼 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 Bismuth
“Astatine”
+

35. •In the early 1940, Edwin Mcmillan and Philip
Abelson discovered the TRANSURANIUM ELEMENTS
(elements heavier than uranium)

36. *TRANSURANIUM ELEMENTS

37. 93
Np
Neptunium
• Neptunium was the first
synthetic transuranium
element (elements after
uranium) of the actinide
series to be discovered.
• Neptunium is harmful due to
its radioactivity.

38. 92
238
𝑈 + 0
1
𝑛 → 93
239
𝑁𝑝 + −1
0
𝛽
Nuclear Reaction on the creation of element
“NEPTUNIUM”

39. • Atoms that have too many neutrons compared to
proton have greater tendency to undergo beta decay
(1 neutron turn into proton and then beta particle is
release)

40. 94
Pu
Plutonium
•Plutonium was first produced and
isolated on December 14, 1940 by
Dr. Glenn T. Seaborg, Joseph W.
Kennedy, Edwin M. McMillan, and
Arthur C. Wahl by deuteron
bombardment of uranium in the 60-
inch cyclotron at the University of
California, Berkeley.

41. 94
Pu
Plutonium
• plutonium (Pu), radioactive chemical
element of the actinoid series of
the periodic table, atomic number 94.
• It is the most important transuranium
element because of its use as fuel in
certain types of nuclear reactors and
as an ingredient in nuclear weapons.
• Plutonium is a silvery metal that takes
on a yellow tarnish in air.

42. •Element 95 was synthesize by
neutron capture. Two neutrons was
absorbed by element 94 then 1
neutron turns into proton.
95
Am
Americium

43. 96
Cm
Curium
97
Bk
Berkelium
• Elements 96,97,98 & 101 was synthesize by alpha particle
bombardment in cyclotron.
98
Cf
Californium
101
Md
Mendelevium

44. • The discovery of the elements 99 & 100 was interesting they
were found from the debris of hydrogen bomb explosion.
The energy from the blast made neutron capture possible
which resulted to the synthesis of many elements including
elements 99 & 100.
99
Es
Einsteinium
100
Fm
Fermium

45. • Elements heavier than element 103 are considered super heavy elements. They
are usually produce or synthesize by bombarding heavy nuclear target with heavy
projectiles.

46. • For example the most recently synthesize element
is Tennessine. It was prepared by the bombardment
of berkelium and calcium.
117
Ts
Tennessine

47. • The heaviest element known so far is element 118
(Oganesson). It was made through the
bombardment of californium with calcium.
118
Og
Oganesson

48. • If you want to create element heavier than Oganesson. You can
try to bombard Calcium and Einstenium .But the problem is the
scarcity of Einstenium