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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 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.
Two elements ‘A’ and ‘B’ belong to the 3rd period of Modern periodic table and are in group 2 and 13, respectively. Compare their following characteristics in tabular form:-
(a) Number of electrons in their atoms
(b) Size of their atoms
(c) Their tendencies to lose electrons
(d) The formula of their oxides
(e) Their metallic character
(f) The formula of their chlorides
Define the term : Valency
Write any one difference in the electronic configurations of group-1 and group-2 elements ?
Which element has twice as many electrons in its second shell as in its first shell?
Classify the following elements into metals, non-metals and metalliods
As, C, Hg, Mg, S, Si
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]
How does the valency of elements change of moving from left to right in the third period of the periodic table?
Arrange the following elements in increasing order of their atomic radii:
Li, Be, F, N
Arrange the following elements in the increasing order of their metallic character:
Mg, Ca, K, Ga
Fill in the blank in the following statement:
The tendency to gain an electron ............... on moving down in a group of the periodic table.
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?
Why do elements in the same group show similar properties but the elements in different groups show different properties?
State one reason for keeping fluorine and chlorine in the same of the periodic table.
In terms of electronic configurations, explain the variation in the size of the atoms of the elements belonging to the same period and same group ?
Five elements A, B, C, D and E have atomic numbers of 2, 3, 7, 10 and 18 respectively. The elements which belong to the same period of the periodic table are:
(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E
The element which has the maximum number of valence electrons is:
(a) Na
(b) P
(c) Si
(d) A
Which one of the following does not increase while moving down the group of the periodic table?
State the valency of the elements of periods 3 and write the formula of their oxides.
Why fluorine has higher E.N. than chorine?
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:
name of the element,
Four elements P, Q, R and S belong to the third period of the Modern Periodic Table and have respectively 1, 3, 5 and 7 electrons in their outermost shells. Write the electronic configurations of Q and R and determine their valences. Write the molecular formula of the compound formed when P and S combine.
An element 'M' has atomic number 12.
(a) Write its electronic configuration.
(b) State the group to which 'M' belongs.
(c) Is 'M' a metal or a non-metal.
(d) Write the formula of its chloride.
Fill in the blank
Oxidising property ________from fluroine to iodine because the power to accpet electron decreases.
Select the correct answer
Identify the metalloid
The following questions refer to the Periodic Table.
What is the common feature of the electronic configurations of the elements in group 7?
Choose the correct answer from the choice given:
An element A belonging to Period 3 and Group II will have
Choose the most appropriate answer from the following list of oxides which fit the description.
A basic oxide.
Atomic numbers of elements A, B, C, D, E, F are 8, 7, 11, 12, 13 and 9 respectively. State the type of ions they form.
Formula of ion of A is A2+. Element A probably belongs to ______ group.
Going across a period left to right, atomic size _____.
Moving left to right in the second period, the number of valence electrons _____.
Write the electronic configuration of two elements A and B whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element A reacts with element B. State whether this compound is acidic, basic or neutral. Give a reason to justify your answer.
What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3?
Name or state following with reference to the element of the first three periods of the periodic table.
The non-metallic element present in period 3 other than sulphur and chlorine.
