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प्रश्न
What are the elements.
उत्तर
“Elements are pure substances made up of one kind of atoms and cannot be broken down into simpler substances.” 118 elements are there.
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संबंधित प्रश्न
What is meant by a period, in a periodic table?
Give two example of group 1 elements.
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.
In the modern Periodic Table, why does cobalt with higher atomic mass of 58.93 appear before nickel having lower atomic mass of 58.71?
Write a short note.
Structure of the modern periodic table.
Give the symbol and valency of the following element and radical.
Sodium
The amount of energy released when one or more electrons is added to the neutral atom is ______
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.
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 |
Which of the element is a Noble gas?
1H2 is an isotope of hydrogen. In the modern Periodic Table it will ______.
