The ionisation energy of hydrogen atom is 13.6eV. What will be the ionisation energy of He+?
13.6 eV
54.4 eV
122.4 eV
Zero
The number of electron and neturons of an element is 18 and 20 respectively. Its mass number is
2
17
37
38
2g of mixture of CO and CO2 on reaction with excess I2O5 produced 2.54g of I2. What would be the mass% of CO2 in the original mixture?
60
30
70
35
When 10g of 90% pure lime stone is heated completely, the volume (in litres) of CO2 is liberated at STP is
22.4
2.24
20.16
2.016
The correct order of radii is
N <Be <B
F-<O2-<N3-
Na< Li< K
Fe3+< Fe2+< Fe4+
B.
F-<O2-<N3-
These are isoelectronic species and their radii decreases with increasing their atomic number due to increasing effective nuclear charge (Zeff).
where, Zeff = effective nuclear charge, Z= atomic number and = screening constant. For F-, O2- and N3-, the value of is the constant due to equal number of electron. So order of Zeff is F > O2-> N3-, hence, order of radii is
Law of constant composition is same as the law of
conservation of mass
conservation of energy
multiple proportion
definite proportion
BCl3 is a planar molecule, while NCl3 is pyramidal, because
N-Cl bond is more covalent than B-Cl bond
nitrogen atom is smaller than boron atom
B-Cl bond is more polar than NCl bond
BCl3 has no lone pair of electrons but NCl3 has a lone pair of electrons.