The first ionisation potential (in eV) of Be and B, respectively are
8.29, 9.32
9.32, 9.32
8.29, 8.29
9.32, 8.29
The first meaningful and remarkable contribution in the field of classification of elements was made by
William Prout
Mendeleev
Cooke
Rutherford
First period contains
two elements
four elements
six elements
eight elements
Which block consists of elements of group(IA)and (IIA) ?
s
p
d
f
The fourteen elements from Th to Lr are known as
Actinides
Lanthanides
Alkalimetals
Noble gases
The horizontal columns in a periodic table are known as
group
period
class
block
Which of the following does not represent the correct order of the properties indicated ?
Which block consists of elements of groups 13(IIIA),14 (IVA) 15(VA),16(VIA),17(VIIA) and 18 ?
In the modified form of Mendeleev's periodic table,all the known elements have been arranged in ten horizontal columns called
series
The ions are isoelectronic. Their ionic radii show
an increases from O2- to F- and then decrease from Na+ to Al3+
a decrease from O2- to F- and then increase from Na+ to Al3+
a significant increase from O2- to Al3+
a significant decrease from O2- to Al3+
