The plot of square root of frequency of X-ray emitted against atomic number led to suggestion of which law/rule?
Periodic law
Modern periodic law
Hund's rule
Newland's law
Which of the following represents the correct order of increasing first ionisation enthalpy for Ca, Ba, S, Se and Ar?
Ca <S<Ba<Se<Ar
S< Se<Ca<Ba< Ar
Ba< Ca<Se< S< Ar
Ba< Ca<Se< S< Ar
The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of Na+ will be
-2.55 eV
-5.1 eV
-10.2 eV
-10.2 eV
The increasing order of the ionic radii of the given isoelectronic species is
Cl-, Ca2+, K+, S2-
S2-, Cl-, Ca2+,K+
Ca2+, K+, Cl-, S2-
Ca2+, K+, Cl-, S2-
The outer electron configuration of Gd (Atomic No : 64) is
4f3 5d5 6s2
4f8 5d0 6s2
4f4 5d4 6s2
4f4 5d4 6s2
D.
4f4 5d4 6s2
The correct sequence which shows decreasing order of the ionic radii of the elements is
Al3+ > Mg2+ > Na+ > F- > O2-
Na+ > Mg2+ > Al3+ > O2- > F-
Na+ > F- > Mg2+ > O2- > Al3+
Na+ > F- > Mg2+ > O2- > Al3+
The set representing the correct order of ionic radius is
Li+> Be2+> Na+> Mg2+
Na+>Li+>Mg2+> Be2+
Li+>Na+ > Mg2+ > Be2+
Li+>Na+ > Mg2+ > Be2+
The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, K+, Ca2+, Mg2+, Be2+?
Mg2+ < Be2+ < K+ < Ca2+
Be2+ < K+ < Ca2+ < Mg2+
K+ < Ca2+ < Mg2+ < Be2+
K+ < Ca2+ < Mg2+ < Be2+
The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first) is
F < S < P < B
P < S < B < F
B < P < S < F
B < P < S < F