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प्रश्न
An element 'X' has mass number 35 and number of neutrons 18. Write atomic number and electronic configuration of 'X'. Also write group number, period number and valency of 'X'.
उत्तर
Mass number of X = 35
Number of neutrons = 18
Atomic number = Mass number – Number of neutrons
= 35 – 18 = 17
Electronic configuration of X = 2, 8, 7
Group of X = 17
Period of X = 3
Valency of X = 1
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संबंधित प्रश्न
Taking the example of an element of atomic number 16, explain how the electronic configuration of the atom of an element relates to its position in the modern periodic table and how valency of an element is calculated on the basis of its atomic number.
The elements Be, Mg and Ca each having two electrons in their outermost shells are in periods 2, 3, and 4 respectively of the modern periodic table. Answer the following questions, giving justification in each case:-
(i) Write the group to which these elements belong.
(ii) Name the least reactive element.
(iii) Name the element having largest atomic radius.
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[Atomic masses: S=32, Ca=40]
Which of the following set of elements is written correctly in the order of their increasing metallic character?
(a) Mg, Al, Si
(b) C, O, N
(c) Na, Li, K
(d) Be, Mg, Ca
An element X belong to 4th period and 17th group, state.
Write the formula of the compound formed when it reacts with `(27)/(13) y `
An element X belong to 3rd periods and group II of the periodic table state:
the number of valence electrons,
The elements of one short period of the periodic table are given below in order from left to right:
Li Be B C O F Ne
(a) To which period do these elements belong?
(b) One element of this period is missing. Which is the missing element and where should it be placed?
(c) Place the three elements, fluorine, beryllium and nitrogen, in the order of increasing electro negativity.
(d) Which one of the above elements belongs to the halogen series?
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
To which period do these elements belong?
The position of elements A, B, C, D and E in the periodic table are shown below:
|
Group 1 |
Group 2 |
Group 17 |
Group 18 |
|
|
|
|
D |
|
|
B |
C |
|
|
A |
|
|
E |
Which type of ion will be formed by elements A, B, and C.
Write the electronic configuration of element 17T35.
- What is the group number of T?
- What is the period number of T?
- How many valence electrons are there in an atom of T?
- What is the valency of T?
- Is it a metal or non-metal?
- State number of protons and neutrons in T.
