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प्रश्न
Atomic number of metal ‚A‛ is 11, while atomic number of metal ‚B‛ is 20. Which of them will be more reactive? Write the chemical reaction of dilute HCl with metal ‚A‛.
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उत्तर
Metal ‘A’ is more reactive than metal ‘B’.
Atomic number of metal ‘A’ is 11, hence it is Na.
`2Na + 2HCI → 2NaCI(aq) + H_2 (g) `
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संबंधित प्रश्न
The atomic numbers of three elements A, B and C are 12, 18 and 20 respectively. State, giving reason, which two elements will show similar properties.
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.
An element 'X' belong to 3rd period and group 13 of the Modern Periodic Table.
(a) Determine the valence electrons and the valency of 'X'.
(b) Molecular formula of the compound formed when 'X' reacts with an element 'Y' (atomic number = 8).
(c) Write the name and formula of the compound formed when 'X' combines with chlorine
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'.
How many groups and periods are there in the modern periodic table?
From the following elements :
4Be; 9F; 19K; 20Ca
(i) Select the element having one electron is the outermost shell.
(ii) two elements of the same group.
Write the formula of and mention the nature of the compound formed by the union of 19K and element X(2, 8, 7).
Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)
Choose the most appropriate answer of the following:
Which of the following would weigh the least?
(A) 2-gram atoms of Nitrogen.
(B) 1mole of Silver
(C) 22.4 liters of oxygen gas at 1 atmospheric pressure and 273K
(D) 6.02 x 1023 atoms of carbon.
[Atomic masses: Ag=108, N=14, O=16, C=12]
An element Z has atomic number 16. Answer the following questions on Z:
- State the period and group to which Z belongs.
- Is Z a metal or a non-metal?
- State the formula between Z and hydrogen.
- What kind of a compound is this?
How does the number of valence electrons vary on moving from left or right in the first period of the periodic table?
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the periodic table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
How does the electropositive character of elements change on going down in a group of the periodic table?
How does Chemical reactivity of elements change on going from left to right in a period of the periodic table?
Give example in support of your answer.
The correct increasing order of the atomic radii of the elements oxygen, fluorine and nitrogen is:
(a) O, F, N
(b) N, F, O
(c) O, N, F
(d) F, O, N
An element X belong to 4th period and 17th group, state.
no of valence electrons in it
An element barium has atomic number 56. Look up its position in the periodic table and answer the following question.
Is it more or less reactive than calcium?
An element X belong to 3rd periods and group II of the periodic table state:
the number of valence electrons,
An element X belong to 3rd periods and group II of the periodic table state:
the valency,
Name the element of lower nuclear charge out of Be and Mg.
How many groups and periods are there in the modern periodic table?
Select the correct answer
Identify the metalloid
What is meant by a group in the periodic table?
How many elements are there in period 2?
Consider the section of the periodic table given below:
| Group numbers | IA | IIA | IIIA | IVA | VA | VIA | VIIA | 0 |
| 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 | |
| Li | D | O | J | Ne | ||||
| A | Mg | E | Si | H | K | |||
| B | C | F | G | L |
Note: In this table B does not represent boron
C does not represent carbon
F does not represent fluorine
H does not represent hydrogen
K does not represent potassium
You must see the position of the element in the periodic table.
Some elements are given in their own symbol and position in the periodic table, while others are shown with a letter. With reference to the table answer the following:
- Which is the most electronegative?
- How many valence electrons are present in G?
- Write the formula of the compound between B and H.
- In the compound between F and J, what type of bond will be formed?
- Draw the electron dot structure for the compound formed between C and K.
Choose the most appropriate answer from the following list of oxides which fit the description.
An amphoteric oxide.
Arrange the following as per the instruction given in the bracket
He,Ar,Ne (Increasing order of the number of electron shells)
Arrange the following as per instruction given in the bracket
Na, K, Cl, S, Si (increasing ionisation potential)
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 |
State which is metals, non-metals, and noble gas in this table.
Moving left to right in the second period, the number of valence electrons _____.
An element A has 2 electrons in its fourth shell. State:
is it a metal or non-metal
What is meant by a Group in the Periodic Table?
Name or state following with reference to the element of the first three periods of the periodic table.
The valency of elements in group 1 [I–A].
Select the correct answer from the options given below.
Is the group number of the element whose atomic number is 4.
Fill in the blanks from the words A to F given below’.
A: Decreases
B: Increases
C: Remains same
D: Increases by one
E: Electropositive
F: Electronegative
Across a period from left to right in the Modern Periodic Table.
No. of electron shells _________; No. of valence electrons __________: Electronegativity increases Character of elements changes from electropositive to ________.
State the following:
The group to which the element with an electronic configuration of 2, 8, 2 belongs.
