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प्रश्न
Moving left to right in the second period, the number of valence electrons _____.
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उत्तर
Moving left to right in the second period, the number of valence electrons increases from 1 to 8.
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संबंधित प्रश्न
Study the following table in which positions of six elements A, B, C, D, E and F are shown as they are in the modern periodic table:
|
Group→
Period↓ |
1
|
2
|
3-12
|
13
|
14
|
15
|
16
|
17
|
18
|
| 2 | A | B | C | ||||||
| 3 | D | E | F |
On the basis of the above table, answer the following questions:-
(i) Name the element which forms only covalent compounds.
(ii) Name the element which is a metal with valency three.
(iii) Name the element which is a non-metal with valency three.
(iv) Out of D and E, which is bigger in size and why?
(v) Write the common name for the family to which the elements C and F belong.
The elements 4Be, 12Mg and 20Ca, each having two valence electrons in their valence shells, are in periods 2, 3 and 4 respectively of the modern periodic table. Answer the following questions associated with these elements, giving reason in each case:
(a) In which group should they be?
(b) Which one of them is least reactive?
(c) Which one of them has the largest atomic size?
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
Which element has a total of two shells, with three electrons in its valence shell?
The atomic number of an element is 20. In modern periodic table, this element is placed:
(a) 2nd period
(b) 4th period
(c) 3rd period
(d) 1st period
The atomic numbers of three elements A, B and C are given below:
| Element | Atomic number |
| A | 5 |
| B | 7 |
| C | 10 |
(i) Which element belongs to group 18?
(ii) Which element belongs to group 15?
(iii) Which element belongs to group 13?
(iv) To which period/periods do these elements belong?
How does the number of:
valency vary on moving from left to right in the second period of the periodic table?
Name the element of lower nuclear charge out of Be and Mg.
An element A has 2 electrons in its fourth shell. State:
is it an oxidising or reducing agent
Which of the following would weigh the least?
(Atomic masses C = 12, 0 = 16, Na = 23)
