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प्रश्न
Find the correlation:
Mendeleev’s periodic table : atomic mass : : Modern periodic table : _______
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उत्तर
Mendeleev’s periodic table : atomic mass : : Modern periodic table : atomic number
Explanation:
Mendeleev organised his periodic table based on the atomic mass of elements. In contrast, the modern periodic table is based on the atomic number (the number of protons), which Henry Moseley demonstrated to be a more fundamental property for predicting periodic trends in chemical behaviour.
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संबंधित प्रश्न
Fill in the following blank with suitable word:
The basis for modern periodic table is ...............
What is meant by a group, in a periodic table?
How many periods and groups are there in the long form of periodic table?
Give two example of group 17 elements.
What is the significance of atomic number in the modern classification of elements? Explain with the help of an example.
On which side of the periodic table will you find non-metals?
Would you place the two isotopes of chlorine, CI-35 and CI-37 in different slots because of their different atomic masses or in the same slot because their chemical properties are the same? Justify your answer.
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
Consider the following elements:
Ca, Cl, Na, I, Li, Ba, Sr, K, Br
Separate these elements into three groups (families) of similar properties. State one property in each case on the basis of which you have made your choice.
What is a group in the periodic table?
In what respects do the properties of group 1 elements differ from those of group 17 elements? Explain with examples by taking one element from each group.
Name two elements in Alkaline earth metals.
Name two elements in each case: Lanthanides
What do you understand by typical elements?
Fill in the blank:
The horizontal rows in the periodic table are called _____________.
An element barium has the atomic number 56. Look up its position in the periodic table and answer the following question.
Is it larger or smaller than caesium (Cs)?
How will the tendency to gain electrons change as we go from left to right across a period? Why?
What is the number of elements in the 3rd period, of the modern periodic table?
Give the symbol and valency of the following element and radical.
Chlorine [Chloride]
Give the symbol and valency of the following element and radical.
Nitrogen [Nitride]
Give the chemical formula of sodium sulphite
State what the group number in the Modern Periodic Table signifies. Give a reason why elements in the same group, have similar valency and similar chemical properties.
State the number of elements in Period 1 of the Periodic Table.
What are the periods in a periodic table?
The d-block elements are called as ______ elements.
Find the correlation:
Group 13 to 18 : p block : : ______ : d block
Right or wrong sentence.
The K and L shells of the elements Na and Mg contain electrons.
Write a scientific reason.
There was ambiguity about the correct position of hydrogen in Mendeleev’s periodic table.
Distinguish between:
Group 17 - Group 18
An X element with atomic number 11 and Y element with atomic number 13 belongs to the third period in the modern periodic table. With this information, give the answers of the below questions.
- Which element has more metallic character from these two elements?
- What is the valency of each X and Y elements?
- Atom size of Y element is smaller than atom size of X element? Explain?
Explain structure of modern periodic table in short.
The inert gas which lies in the third period is ______
Where would you locate the element with electronic configuration 2,8 in the Modern Periodic Table?
Which of the following is the outermost shell for elements of period 2?
The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?
An element X which is a yellow solid at room temperature shows catenation and allotropy. X forms two oxides which are also formed during the thermal decomposition of ferrous sulphate crystals and are the major air pollutants.
- Identify the element X
- Write the electronic configuration of X
- Write the balanced chemical equation for the thermal decomposition of ferrous sulphate crystals?
- What would be the nature (acidic/ basic) of oxides formed?
- Locate the position of the element in the Modern Periodic Table.
Spot the error:
The elements of group 13 are called the carbon family.
Match the atomic number with the following:
A rare gas.
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?
