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The group number, number of valence electrons, and valency of an element with atomic number 15, respectively, are:

• Option 1)

$15,5$ and $3$

• Option 2)

$16,6$ and $3$

• Option 3)

$16,5$ and $2$

• Option 4)

$15,6$ and $2$

P Block elements - P block elements comprise those belonging to group 13 to 18  and together with the  S block elements are called the main group elements.Outer most configuration varies from  ns2 np1  to  ns2np6 in each period. -       The element with atomic number is phosphorus. Thus, its Group number = or VA valence electrons =  valency =   Option (1) is correct   Option 1)  and  Option...

The isoelectronic set of ions is :

• Option 1)

$N^{3-}, O^{2-},F^{-} \: \: and \: \: Na^{+}$

• Option 2)

$N^{3-}, Li^{+},Mg^{2+} \: \: and \: \: O^{2-}$

• Option 3)

$F^{-},Li^{+}, Na^{+} \: \: and \: \: Mg^{2+}$

• Option 4)

$Li^{+},Na^{+},O^{2-} \: \: and \: \:F^{-}$

Isoelectronic species are those species that have the same  number of electrons.   are isoelectronic species & have  same number of electrons equal to 10. option (1) is correct.Option 1)Option 2)Option 3)Option 4)

The correct order of the first ionization enthalpies is :

• Option 1)

$Ti< Mn< Zn< Ni$

• Option 2)

$Ti< Mn< Ni< Zn$

• Option 3)

$Mn< Ti< Zn< Ni$

• Option 4)

$Zn< Ni< Mn< Ti$

moving from left to right I.E increases. Option 1) Option 2)Option 3)Option 4)

The element having greatest difference between its first and second ionization energies, is :

• Option 1)

$Ca$

• Option 2)

$Sc$

• Option 3)

$Ba$

• Option 4)

$K$

is from first group   are from second group .  , after  it will reach Noble gas configuration and its  will be very high,     Option 1) Option 2) Option 3) Option 4)

The size of the iso-electronic species $Cl^{-},Ar$ and $Ca^{2+}$ is affected by :

• Option 1)

azimuthal quantum number of valence shell

• Option 2)

nuclear charge

• Option 3)

electron-electron interaction in the outer orbitals

• Option 4)

Principal quantum number of valence shell

For isoelectronic species the size is compared  by Nuclear charge.Option 1)azimuthal quantum number of valence shellOption 2)nuclear chargeOption 3)electron-electron interaction in the outer orbitalsOption 4)Principal quantum number of valence shell

In comparison to boron, beryllium has:

• Option 1)

lesser nuclear charge and lesser first ionisation enthalpy

• Option 2)

greater nuclear charge and lesser first ionisation enthalpy

• Option 3)

greater nuclear charge and greater first ionisation enthalpy

• Option 4)

lesser nuclear charge and greater first ionisation enthalpy

"Be" has 4 proton  & "B" has 5 protons so, Nuclear charge of "Be" is less than "B" And half filled is more stable than partially filled orbitals.  IE1 ---  Be  >    B            2s2        2p1   Option 1) lesser nuclear charge and lesser first ionisation enthalpy Option 2) greater nuclear charge and lesser first ionisation enthalpy Option 3) greater nuclear charge and greater first...

The pair that has similar atomic radii is:

• Option 1)

Mn and Re

• Option 2)

Ti and Hf

• Option 3)

Sc and Ni

• Option 4)

Mo and W

Option 1) Mn and Re Option 2) Ti and Hf Option 3) Sc and Ni Option 4) Mo and W

The correct option with respect to the Pauling electronegativity values of the elements is :

• Option 1)

Ga < Ge

• Option 2)

P > S

• Option 3)

Si < Al

• Option 4)

Te > Se

Electronegativity - A qualitative measure of the ability of an atom in a chemical compound to attract shared electron is electronegativity. - wherein It is not a measurable quantity.     Electronegativity and non-metallic character - Non-metallic elements have strong tendency to gain electrons.Therefore electronegativity is directly related to non-metallic properties of elements. -...

The element that shows greater ability to form $p\pi -p\pi$ multiple bonds, is :

• Option 1)

Sn

• Option 2)

Ge

• Option 3)

C

• Option 4)

Si

Bonding Behaviour of P-block Elements - Most of them are non-metal and form both covalent and ionic bonds.Most of the non-metals have polyatomic molecules. -    carbon has the most tendency to form P(pie)-P(pie) multiple bonding. As we have learned is chemical bonding. We know that carbon atom have 2p orbital and it is able to form strongest bond  Option 1)SnOption 2)GeOption 3)COption 4)Si

The electronegativity of aluminium is similar to :

• Option 1)

Carbon

• Option 2)

Beryllium

• Option 3)

Boron

• Option 4)

Lithium

@peri  Modern periodic law - The physical and chemical properties of elements are periodic functions of their atomic number. -     Periodicity - Regular variation in physical and chemical properties are observed down the group () or along the period (→) in the periodic table.The regular gradation in properties is called periodicity. -   we have lernt about electrnegativity EN of  1.5 which is...

When the first electron gain enthalpy $\left ( \Delta _{eg}H \right )$ of oxygen is -141kJ/mol , its second electron gain enthalpy is :

• Option 1)

A more  negative value than the first .

• Option 2)

Almost the same as that of the first .

• Option 3)

Negative , but less  negative than the first .

• Option 4)

A positive value .

Electron gain enthalpy - When an electron is added to a neutral gaseous atom (x) to convert it into a negative ion, the enthalpy change accompanying the process is defined as the electron gain enthalpy  - wherein The second electron gain ethalpy is always positive for elements.     Variation of electron gain enthalpy with electronic configuration - Elements with half or full filled...

In general ,the properties that decrease and increase down a group in the periodic table ,respectively are :

• Option 1)

• Option 2)

electron gain enthalpy and electronegativity

• Option 3)

• Option 4)

electronegativity and electron gain enthalpy

Mendeleev's periodic table - Mendeleev arranged the 63 discovered elements in the periodic table in to 7 horizontal rows known as periods and vertical column known as groups numbered 1 to 8. -     Electronegativity and atomic radius - The attraction between the outer electrons and the nucleus increases as the atomic radius decreases in a period. - wherein     As we know that as we go down...
Engineering
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The increasing order of the ionic radii of the given isoelectronic species is :

• Option 1)

• Option 2)

• Option 3)

• Option 4)

3

Engineering
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Which of the following represents the correct order of increasing first ionization enthalpy for Ca,Ba,S ,Se and Ar?

• Option 1)

Ca < Ba < S < Se < Ar

• Option 2)

Ca < S < Ba < Se < Ar

• Option 3)

S < Se < Ca < Ba < Ar

• Option 4)

Ba < Ca < Se < S < Ar

How

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