Advertisements
Advertisements
Question
Write two reasons responsible for late discovery of noble gases ?
Solution
Two reasons for late discoveries of noble gases are:-
(a) They are very inert.
(b) They are present in extremely low concentrations in our environment.
APPEARS IN
RELATED QUESTIONS
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'.
An element 'M' with electronic configuration (2, 8, 2) combines separately with (NO3)–, (SO4)2– and (PO4)3– radicals. Write the formula of the three compounds so formed. To which group and period of the Modern Periodic Table does the element 'M' belong? Will 'M' form covalent or ionic compounds? Give reason to justify your answer.
Calculate the mass of Calcium that will contain the same number of the atom as are present in 3.2 gm of Sulphur.
[Atomic masses: S=32, Ca=40]
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 electronic configuration of the atom of an element X is 2, 8, 4. In modern periodic table, the element X is places in :
(a) 2nd group
(b) 4th group
(c) 14th group
(d) 8th group
How can the valency of an element be determined if its electronic configuration is known?
Fill in the blank
Oxidising property ________from fluroine to iodine because the power to accpet electron decreases.
The following questions refer to the Periodic Table.
Name the first and last element in period 2.
Arrange the following as per instruction given in the bracket
Na, K, Cl, S, Si (increasing ionisation potential)
