Assertion : Barium is not required for normal biological function in human.
Reason : Barium does not show variable oxidation state.
If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
The atomic number of cerium (Ce) is 58. The correct electronic configuration of Ce3+ ion is.
[Xe] 4f1
[Kr] 4f1
[Xe] 4f13
[Kr] 4d1
The decreasing order of basic character of K2O, BaO, CaO and MgO is
K2O > BaO > CaO > MgO
K2O > CaO > BaO > MgO
MgO > BaO > CaO > K2O
MgO > CaO > BaO > K2O
Which of the following is correct?
Radius of Ca2+ < Cl- < S2-
Radius of Cl- < S2- < Ca2+
Radius of Cl- = S2- = Ca2+
Radius of S2- < Cl- < Ca2+
If the first ionization energy of H atom is 13.6 eV, then the second ionization energy of He atom is:
27.2 eV
40.8 eV
54.4 eV
108.8 eV
Which one of the following has the lowest ionisation energy?
1s2 , 2s2 , 2p6
1s2 , 2s2 , 2p6 , 3s1
1s2 , 2s2 , 2p5
1s2 , 2s2 , 2p3
Which of the following statements about the interstitial compounds is incorrect?
They retain metallic conductivity
They are chemically reactive
They are much harder than the pure metal
They have higher melting points than the pure metal
In Periodic Table, the basic character of oxides
increases from left to right and decreases from top to bottom
decreases from right to left and increases from top to bottom
decreases from left to right and increases from top to bottom
decreases from left to right and increases from bottom to top