P block elements Flashcards
How many grps are in p block
6
The exception of p block electronic configuration is
He
The maximum oxidation number of p block is
Total number of valence electrons in s and p
The occurrence of oxidation state two units less than the grp oxidation state is because of
Inert pair effect
For heavier elements the stable oxidation state would be
Two unit less than grp oxidation state
Where in the periodic table does non Metals and metalloids exist
P block
Which has higher ionization enthalpy and high electronegativity
Non metals
The first members of p block difrers from other members in their ability to form p pi = p pi bonds
True
The heavier elements of p block forms p pi = d pi bonds or d pi= d pi bonds
True
As d orbitals are of high energy they contribute less to the stability of the molecules than p pi = P pi bond
True
Boron occurs as
Orthoboric acid ( H3BO3)
Kernite Na2B4O7.4 H2O
Borax Na2B4O7. 10 H20
Important ore of aluminium is
Bauxite Al2O3.2H20
Cryolite Na3AlF6
The atomic radius of Ga is less than that of Al
Due to Poor screening effect
The reason for decrease in ionization enthalpy between B and Al
Increase in size
The reason for decrease in ionization enthalpy Al and Ga, In and Tl is due to
Low screening effect of d and f electrons
The electronegativity in 13th grp decreases from
B to Al
The electronegativity in 13th grp Increases from
Al to Tl
Tendency to form Lewis acid decreases with
Increase in size down the grp
AlCl3 achieves stability as a dimer
True
Boron is reactive in chtystalline form
False
Amorphous Boron is reactive
True
Boron trioxide is
Acidic in natureb
Aluminium and Gallium oxides
Amphoteric oxides
Indium and thallium oxides are
Basic
Concentrated nitric acid renders aluminum passive by forming a protective oxide layer
True
P block elements react with halogens to form
Trihalides ( except Tl I3)
White fumes appear around-the-bottle of
Anhydrous aluminium chloride
Carbon is
17th most abundant
Which 14 grp element exist as traces
Germanium
Tin occurs mainly as
Casseterite ( SnO2)
Lead occurs mainly as
Galena ( PbS)
Considerable increase in covalent radius from
C to Si
Small increase in covalent radius from
Si to pb ( due to completely filled D and f orbitals in heavier metals)
Ionization enthalpy of grp 14 elements is
More than that of 13 elements
Due to Small size elements of 14 grp element are more electronegative than 13 grp element
True
SiO2 and GeO2 is
Acidic
Arsenic and antimony are
Metalliods
Bismuth is
Metal
Considerable increase in Ionic radii in grp 15 from
N to P
Small increase in Ionic radii from
As to Bi ( completely filled D and f orbitals in heavier members )
Grp 15 elements have higher ionization enthalpy than
Grp 14
With increasing atomic radii electronegativity
Decreases
Except which element all the others show alloptropy in grp 15 elements
Nitrogen
Melting point in grp 15 elements increases
Upto arsenic and then decreases upto bismuth
The boiling point of 15th grp element
Increases down the grp
Common oxidation state of 15th grp element
-3, +3, +5
Oxidation states of Nitrogen that tend to undergo disproportion in acidic medium
+1 to +4
Max covalency of Nitrogen is
4
Which oxidation state with resp to As, Sb, Bi is more stable in disproportionately
+3
Heavier metals of grp 15 does not form
P pi p pi bond
Single N- N bond is weaker than single P-P bond
True
Catenation tendency of Nitrogen is
Weak
Stability of hydride in grp 15 is
Decreases from NH3 to BiH3
WHich is high reducing agent NH3 or BiH3 ?
BiH3
Order of basicity in grp 15 elements
Decreases from NH3 to BiH3
Higher oxidation state oxides are more
Acidic
Grp 15 elements show what type of oxides
E2O3 and E2O5
Nitrogen does not form pentahalides due to
Unavailability of d orbital
Pentahalides are more which property than trihalides
Covalency
The only stable trihalide of N
NF3
A: all trihalides except that of N are stBle
R: trihalides except BF3 are covalent in nature
Both are corect
SbOCl colour
Orange
BiOCl
White
Halides are hydrolyzed in water to form
Oxyacids and oxychlorides
Grp 15 elements react with metals in which ox state
-3
The most basic trihalide of Nitrogen is
NI3
The bond angle of hydride in p block
Decreases that is NH3 has greatest and BiH3 has least
Nitrogen is chemically inert because
Of high bond energy
Grp 16 elements are
Chalcogens
Chalcogens are known as such because they form
A major component of ore are oxides or sulphides
The negative value of electron gain enthalpy in 16th grp
Decreases down the grp
Radioactive grp 16 element
Polonium
Large diffrence in boiling and melting point exist between in grp 16
Oxygen and sulfur( explained on the basis of their atomicity oxygen is diatomic while sulfur is polyatomic
Catenation is predominantly present in grp 16
Sulfur( S-S bond in cystein)
Which 16th grp element is used in photoconductivity
Selenium
The stability of -2 oxidation state down the grp(16)
Decreases
The stability of +6 oxidation state( 16th grp)
Dectease down the grp ( inert pair effect)
The stability of +4 oxidation state(16th grp)
Increases down the grp ( inert pair effect)
HNO3 oxidizes Sulphur to H2SO4 but only oxidize selenium to H2SeO3
As the atoms are smaller and due to Poor shielding effect of 3d electrons the electrons are more tightly held with nucleus
Oxygen does not directly react with
Chlorine
