s-Block ElementsHard
Question
Select the correct statement with respect to alkali metals.
Options
A.Melting points decrease with increasing atomic number.
B.Potassium is lighter than sodium.
C.Salts of Li to Cs impart characteristic colour to an oxidising flame. (of Bunsen burner).
D.All of these.
Solution
(A) Down the group due to increase in size the strength of metallic bond decreases and so, melting point decreases.
(B) Atomic volume of K is larger as compared to Na. Increase in atomic mass does not over come the effect of increase atomic volume in case of potassium.
(C) They have low ionisation energies because of their larger atomic size. The heat from the flame excites the outer most orbital electron to a higher energy level. When the excited electrons come back to the ground state, there is emission of radiation in the visible region. Hence, salts of Li to Cs impart characteristic colour to an oxidising flame. (of Bunsen burner).
(B) Atomic volume of K is larger as compared to Na. Increase in atomic mass does not over come the effect of increase atomic volume in case of potassium.
(C) They have low ionisation energies because of their larger atomic size. The heat from the flame excites the outer most orbital electron to a higher energy level. When the excited electrons come back to the ground state, there is emission of radiation in the visible region. Hence, salts of Li to Cs impart characteristic colour to an oxidising flame. (of Bunsen burner).
Create a free account to view solution
View Solution FreeMore s-Block Elements Questions
Molecular formula of Glauber′s salt is :...Which is/are not correct configuration of s-block elements :...The principal products obtained on heating iodine with concentrated caustic soda solution is :...Nitrolium is :...When magnesium burns in air, compounds of magnesium formed are magnesium oxide and :...