this presentation is based on chapter one of class 10 (maharashtra board).. this includes description about how was the modern periodic table was made..
Module for Grade 9 for Asynchronous/Distance learning
school of elements
1.
2. Unit Name of the Chapters
Marks
Marks with
optionSection A ( For Paper 1)
1 School of Elements 4 5
2 The Magic of Chemical Reactions 4 5
3 The Acid Base Chemistry 4 5
4 The Electric Spark 5 8
5 All about Electromagnetism 6 7
6 Wonders of Light Part - I 7 8
7 Wonders of Light Part – II 6 7
Section B ( For Paper 2)
8 Understanding Metals and Non- Metals 7 8
9 Amazing World of Carbon Compounds 5 7
10 Life's Internal Secrets 6 8
11 The Regulators of Life 6 7
12 The Life Cycle 6 7
13 Mapping our Genes 6 8
14 Striving for Better Environment 4 5
15 Striving for Better Environment 4 5
Total 80 100
3. Paper pattern
Q.1) subquestion (A) 5 subquestions of 1 mark each ------
total 5 marks
subquestion (B) 5 subquestions of 1 mark each
(MCQs ) ------total 5 marks
Q.2) 6 subquestions of 2 marks each.
any 5 to be attempted----- total 10 marks
Q.3) 6 subquestions of 3 marks each. Any 5 to be
attempted------ total 15 marks
Q.4) 2 questions of 5 marks each. Any 1 to be attempted--
--- total 5 marks
total marks 40
15. PREDICTED ELEMENT ACTUAL ELEMENT DISCOVERED
LATER
Eka-boron Scandium
Eka-aluminium Gallium
Eka-silicon Germanium
16.
17. Modern Periodic Table
• Atomic number is the fundamental property
• What is atomic number
• The Modern Periodic law states that “ The
chemical and physical properties of elements
are a periodic function of their atomic
numbers”
18. Mendeleevs
periodic table
Modern periodic table
Atomic mass Atomic number
Isotopes had different atomic
mass
Isotopes had same atomic
number
Elements of higher atomic
mass had been placed before
Elements of higher atomic
weight had been placed after
66 elements known 118 elements know now
21. Periods in Modern Periodic table
• Same number of shells which is equal to the
period number
• Filling up of new shells
• First period shortest period 2 elements
• Second and third short period 8 elements
• Fourth and fifth long periods 18 elements
• Sixth longest period 32 elements
• Seventh period is Incomplete
22. Groups in Modern Periodic table
• Elements have same number of valence
electrons
• Elements present in same group show similar
chemical properties
• Group 1 Alkali metals
• Group 2 Alkaline earth metals
• Group 17 contains halogens
• Group 18 contains inert gases
26. • Elements in modern periodic table are
classified on basis of their electronic
configuration. They are divided into 4 blocks :
s block, p block, d block and f block
27.
28. • Atomic size increases down the group
• i. The atomic numbers of the elements
increase as we go down the group. Thus, the
elements placed lower have more electrons.
• ii. To accommodate these electrons
new shells are added to the atom.
•
iii. These new shells take the outermost
electrons farther from the nucleus causing atomic
size (radius) to increase as we go down the
group.
29. • Metallic character decreases from left to right in a period
• i. Atoms of metals tend to lose electrons,
whereas those of non – metals tend to gain them.
• ii. In a period, as we go from left to right, atomic
number increases, increasing the number of electrons and
protons.
• iii. These additional electrons are placed in the
same outer shell and are strongly attracted towards the
positively – charged nucleus.
•
iv. This strong attraction does not allow loss of
electrons, causing metallic character to decrease from left
to right in a period.
30. • Elements in the same group show the same valency
• i. Valency is the number of electrons given, taken or
shared by an atom to complete its outermost shell.
•
• ii. All the elements in the same group have the same
number of electrons in their outermost shells.
•
• iii. Thus, all these elements take, give or share the same
number of electrons.
•
• Hence, elements in the same group show the same valency.
31. • Q.I (A) Fill in the blanks :
• 1. The horizontal rows in the periodic table are
....................... .
• 2. From left to right, the atomic size of an atom
....................... .
• 3. There are ....................... periods in the
periodic table..
• 4. An element is placed in group II A, so the
number of valence electrons is ....................... .
• 5. An element is placed in 2nd period, so it has
....................... shells.
32. • 6. Noble gases have valency as ....................... .
• 7. Metals have a tendency to ....................... electrons..
• 8. Valency across a period ....................... .
• 9. Valency down the group ....................... .
• 10. Elements of group I A and II A are ....................... .
• 11. An atom is said to be a non-metal if it
....................... electrons.
• 12. ....................... is the only element in duplet state.
13. The electronic configuration of Neon is
....................... .
• 14. Sodium is a ....................... .
• 15. Silicon and antimony are .......................
33. • 16. Group 1A is called ....................... .
• 17. Group II A is called as ....................... .
• 18. Group VII A is called as ....................... .
• 19. The chemical properties down the group
....................... .
• 20. First period contains ....................... elements.
• 21. Moseley arranged elements according to
....................... .
• 22. The non-metals are present in ....................... .
• 23. The number of shells down the group
....................... . 24. The transition character of
elements is from ....................... to .......................
.
34. • *25. The formula of chloride of metal is MCl 2,
the metal M belongs to ....................... group.
*26. ....................... group contains all gases at
room temperature.
• *27. The arrangement of elements in a group of
three is called ....................... .
• *28. The law used by Newlands to arrange
elements is called ....................... .
• *29. Elements showing properties of both metals
and non-metals are called as ....................... .
• *30. The element eka-Aluminium is called as
.......................
35. • Answers : 1. periods 2. decreases 3. 7 4. 2 5. 2
6. 0 7. donate 8. varies gradually 9. ramains
the same 10. metals 11. gains or shares 12.
Helium 13. 2, 8 14. metal 15. metalloids 16.
alkali metals 17. alkaline earth metals 18.
halogens 19. remain the same 20. 2 21.
Atomic number 22. upper right hand corner
23. increases 24. metallic to Non-metallic 25. II
A 26. 18 or zero 27. triad 28. Newlands Law of
octaves 29. metalloids 30. gallium.
36. • Q.I (C) State whether the following statements
are true or false.
• 1. Atomic number is the number of protons or
electrons in the nucleus.
• 2. Fourth and fifth periods are longest periods.
• 3. Newlands arranged elements based on their
atomic number.
• 4. Mendeleev was the first scientist to create a
periodic table for the elements.
• 5. Mendeleev arranged 63 elements in the
periodic table.
• 6. Eka boron is known as Germanium.
37. • 7. Tellurium, Polonium are metalloids.
• 8. Isotopes have same atomic masses.
• 9. Isotopes have similar chemical properties
• 10. La stands for Lutetium.
• 11. s-block includes I A, II A and hydrogen.
• 12. d-block elements are called normal elements.
• 13. f-block elements are metalloids.
• 14. Metalloids are also called as semi-metals.
• 15. Bordering the zig-zag line are elements called as
metalloids.
• 16. In an atom of an element, extra-nuclear electrons
take part in the chemical reaction.
• 17. The number of shells increases down the group 18.
38. Q.I (G) Give two names of the following :
1. Member of 1st period :
2. Member of 2nd period :
3. Alkali metals :
4. Alkaline earth metals :
5. Member of 3rd period :
6. Elements of zero group :
7. Elements of halogen family :
8. Metalloid : Silicon, Antimony
39. • Q.II (A) State the following :
• 1. Dobereiner’s triads law.
• 2. Newlands law of octaves.
• 3. Mendeleev’s periodic law.
• 4. Modern periodic law.
40. • Q.IV Distinguish between :
• 1. Periods and Groups.
• 2. Alkali metals and Alkaline earth metals
41. • Q.V Answer the following in detail :
• 1. Explain Dobereiner’s law of triads giving examples
• 2. Explain the limitations of Dobereiner's law of triads
• 3. Explain Newlands law of octaves giving examples.
• 4. Explain the limitations of Newlands law of octaves
• 5. Explain the merits of Mendeleevs periodic table.
• *6. Explain the demerits of Mendeleevs periodic table.
• 7. Explain the modern periodic table.
• *8. Explain the merits of modern periodic table. OR
How could the modern periodic table remove various
anomalies of Mendeleev's table?
42. • 9. Explain the four blocks of periodic table
• 10. Explain the zig-zag line in the periodic table.
• 11. Explain the term periodic properties and
explain the following trends of the periodic table
with respect to : 1. Valency 2. Metallic character
*3. Atomic size
• 12. What are the causes of the periodicity of
elements?
• 13. State Dobereiners law of triads. P, Q, R are
elements of a Dobereiner's triad. If atomic mass
of P is 35.5 and R is 127, what would be the
atomic mass of Q?
43. • 14. Why is atomic number said to be a
fundamental property?
• 15. Explain the features of Mendeleev's
periodic table.
• 16. Among the first twenty elements, which
are metals, non-metals and metalloids?
44. • . Atomic radii of elements of third period are
given below.
• Period 3 elements S Na Cl P Mg Si
• Atomic radius (pm) 127 190 99 128 160 132
1. Arrange them in the decreasing order of their
atomic radii.
2. Which are the atoms of highest and lowest
atomic radii ?
3. What trend is observed in the atomic radii in
a period from left to right ?
