The effective nuclear charge at the periphery of chromium atom [Z = 24];
1. 4.25
2. 2.60
3. 3.60
4. 1.21
Which of the following statement is correct ?
1. A 4s-orbital is filled earlier than a 3d-orbital because, Z* for 3d>Z* for 4s
2. A 4s-orbital is filled earlier than a 3d-orbital because, energy for 4s < energy for 3d
3. The effective nuclear charge for 3d and 4s orbitals are same, but energy of 3d-orbital becomes higher
4. The effective nuclear charge for 3d and 4s orbitals are same, but energy of 4s-orbital becomes higher
According to Slater's rule, order of effective nuclear charge (Z*) for last electron in case of Li, Na and K
1. Li > Na > K
2. K > Na > Li
3. Na > Li > K
4. K = Na > Li
How does the energy gap between successive energy levels in an atom vary from low to high values ?
1. All energy gaps are the same
2. The energy gap decreases as n increases
3. The energy gap increases as n increases
4. The energy gap changes unpredictably as n increases
Which of the following is the incorrect match for atom of element ?
1.
2.
3.
4.
Incorrect order of ionic size is :
1.
2.
3.
4.
Consider the following changes :
The second ionisation energy of M could be calculated from the energy values associated with :
1. 1+3+4
2. 2-1+3
3. 1+5
4. 5-3
The incorrect statement is :
1. The second ionisation energy of Se is greater than that of second ionisation energy of As
2. The first ionisation energy of ion is greater than that of first ionisation energy of ion
3. The third ionisation energy of F is greater than that of ionisation energy of O
4. Halogens have highest I.E. in respective period
First three ionisation energies (in kJ/mol) of three representative elements are given below :
Element
P 495.8 4562 6910
Q 737.7 1451 7730
R 577.5 1817 2745
Then incorrect option is :
1. Q : Alkaline earth metal
2. P : Alkali metals
3. R : s-block element
4. They may be member of the same period
If the ionization enthalpy and electron gain enthalpy of an element are 275 and 86 kcal respectively, then the electronegativity of the element on the Pauling scale is :
1. 2.8
2. 0.0
3. 4.0
4. 2.6