Advertisements
Advertisements
प्रश्न
Write the merits of the modern periodic table over Mendeleev’s Periodic table
Advertisements
उत्तर
1) Elements are arranged on the basis of increasing atomic number which is more fundamental.
2) Isotopes of an element can be placed along with parent element.
3) It explains periodicity of properties of elements configuration.
4) Lanthanides and actinides are placed separately.
5) Anomalous pairs of elements like Ar and K having same atomic mass could be justified
APPEARS IN
संबंधित प्रश्न
How does the tendency of elements to gain electrons change as we move from left to right in a period? State the reason of this change.
Fill in the following blank with suitable word:
Group 18 elements are called ...............
What is meant by a group, in a periodic table?
What is the significance of atomic number in the modern classification of elements? Explain with the help of an example.
What is the name of those elements which divide metals and non-metals in the periodic table?
The atomic particle whose number in the atoms of an element always remains the same and which forms the real basis for the modern classification of elements is:
(a) electron
(b) proton
(c) neutron
(d) meson
Give alongside is a part of the periodic table :
As we move horizontally from left to right:
| Li | Be | B | C | N | O | F | |
| Na | Mg | Al | Si | P | S | Cl |
(i) What happens to the metallic character of the elements?
(ii) What happens to the atomic size?
How would the tendency to lose electrons change as we go from left to right across a period of the periodic table?
How does the chemical reactivity of the halogens vary on going in group 17 of the periodic table?
State whether the following statement is true or false:
On going down in a group of the periodic table, the number of valence electrons increases.
What is a period in a periodic table?
What is the number of elements is 1st period the modern periodic table?
What are the periods in a periodic table? Give two characteristics of each.
The atomic numbers of the three elements X, Y and Z are 2, 6 and 10 respectively.
(i) Which two elements belong to the same group?
(ii) Which two elements belong to the same period?
Give reasons for your choice.
Consider the following elements:
20Ca, 8O, 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be:
(i) very stable?
(ii) in group 2 of the periodic table?
(iii) in group 16 of the periodic table?
State the term
The tabular arrangement of elements in horizontal rows and vertical columns _________
What are horizontal rows and vertical columns in a periodic table known as?
Name two elements in each case:
Actinides
What do you understand by typical elements?
An element E has following electronic configuration:
|
K |
L |
M |
|
2 |
8 |
6 |
(a) To which group of the periodic table does element E belong?
(b) To which period of the periodic table does element E belong?
(c) State the number of valence electrons present in element E.
(d) State the valency of the element E.
What is meant in the periodic table by a period?
Name an element of group 18 which can form compounds.
Give the symbol and valency of the following element and radical.
Ammonium
Give the symbol and valency of the following element and radical.
Sulphite
Give the chemical formula of sodium nitrate
Give the chemical formula of sodium sulphite
State the number of elements in Period 2 of the Periodic Table.
What are the elements.
Which of the following statements about the Modern periodic table is correct?
Find the correlation:
Group 1 and 2 : s block : : group 13 and 18 : ______
Write an explanation.
Period
______ forms the basis of the modern periodic table.
On moving from left to right in a period in the periodic table, the size of the atom ______
Which one of the following elements exhibit maximum number of valence electrons?
Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.
Spot the error:
There are 5 periods and 17 groups in the modern periodic table.
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Write the molecular formula of the compound formed by the combination:
A and F
Give the criteria on the basis of which elements are placed (i) in a group and (ii) in a period in the modern periodic table. The atomic number of an element is 16. According to the criteria, in which group and period it should be placed?
Give reason for the following:
Inert gases do not form ion.
A group of elements in the periodic table is given below (Boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following question in relation to the above group of elements:
If the electronic configuration of aluminium is 2, 8, 3, how many electrons are there in the outer shell of thallium?
