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Effective nuclear charge (Z(eff)) for a ...

Effective nuclear charge `(Z_(eff))` for a nucleus of an atom is defined as

A

shielding of the outermost shell electrons from the nucleus by the innermost shell electrons

B

the net positive charge experienced by electron from the nucleus

C

the attractive force experienced by the nucleus from electron

D

screening of positive charge on nucleus by innermost shell electrons

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The correct Answer is:
B
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The second ionization potential of Be is 17.98 eV if the electron in Be is assumed to move in a spherical orbit with a central field of effective nuclear charge (Z_(eff)) consisting of the nucleus and other electron by haw many units of charge in the nucleus shielded by other electrons? (the energy of electrons in first Bohr of H is -13.6 eV) If the extent of shielding by the if electron of Li atom is the same as you have calculated above , find the ionization potential of Li

Tell the relation between effective nuclear charge (Z_(eff)) atomic number (Z) and shielding constant (sigma) . Explain it qualitatively.

Effective nuclear charge (Z_(eff)) is the net attractive force on electrons under consideration and is equal to: Z_(eff) = Z - sigma (nuclear charge - screening constant). Z_(eff) or sigma is calculated by Slater's formula, as given. If one electrons is present in the outermst orbit, there will be no screening in that orbital. Each electrons contribute, 0.35 (total electrons minus one electron) present in the outermost shell. A contribution of 0.85 for each electrons is taken in the (n - 1)th shell. Which of the following statement is wrong?

Effective nuclear charge (Z_(eff)) is the net attractive force on electrons under consideration and is equal to: Z_(eff) = Z - sigma (nuclear charge - screening constant). Z_(eff) or sigma is calculated by Slater's formula, as given. If one electrons is present in the outermst orbit, there will be no screening in that orbital. Each electrons contribute, 0.35 (total electrons minus one electron) present in the outermost shell. A contribution of 0.85 for each electrons is taken in the (n - 1)th shell. Which of the following statement is wrong?

Effective nuclear charge (Z_(eff)) is the net attractive force on electrons under consideration and is equal to: Z_(eff) = Z - sigma (nuclear charge - screening constant). Z_(eff) or sigma is calculated by Slater's formula, as given. If one electrons is present in the outermst orbit, there will be no screening in that orbital. Each electrons contribute, 0.35 (total electrons minus one electron) present in the outermost shell. A contribution of 0.85 for each electrons is taken in the (n - 1)th shell. The screening constant (sigma) for 4s electron of Mn (Z = 25) will be

J.C. Slater proposed an empirical constant that represents the cumulative extent to which the other electrons of an atom shield (or screen) any particular electron from the nuclear charge. Thus, slater's screening contant sigma is as : Z^(**)=Z-sigma Here, Z is the atomic number of the atom, and hence is equal to the actual number of protons in the atom. the parameter Z^(**) is the effective nuclear charge, which according to is smaller than Z, since the electron in question is screened (shielded) from Z by an amount sigma . Conversely, an electron that is well shielded from the nuclear charge Z experiences a small effective nuclear charge Z^(**) . The value of sigma for any one electron in a given electron configuration (i.e., in the presence of the other electrons of the atom in question) is calculated using a set of empirical rules developed by slater. according to these rules, the value of sigma for the electron in question is the cumulative total provided by the various other electrons of the atom. Q. According to Slater's rule, order of effective nuclear charge (Z^(**)) for last electron in case of Li, Na and K.

Arrange s,p and d subshells of a shell in the increasing order of effective nuclear charge (Z_(eff)) experienced by the electron present in them.

Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge Z^(**) actuall ydepends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is s gt p gt d gt f (for the same value of n) The phenomenon in which penultimate shell electrons act as screen or sheild in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. the penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. it is thus evident that more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy. Q. Which of the following valence electron experience maximum effective nuclear charge?

Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge Z^(**) actuall ydepends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is s gt p gt d gt f (for the same value of n) The phenomenon in which penultimate shell electrons act as screen or sheild in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. the penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. it is thus evident that more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy. Q. Which of the following is not concerned to effective nuclear charge?

Nuclear charge actually experienced by an electron is termed as effective nuclear charge. The effective nuclear charge Z^(**) actuall ydepends on type of shell and orbital in which electron is actually present. The relative extent to which the various orbitals penetrate the electron clouds of other orbitals is s gt p gt d gt f (for the same value of n) The phenomenon in which penultimate shell electrons act as screen or sheild in between nucleus and valence shell electrons and thereby reducing nuclear charge is known as shielding effect. the penultimate shell electrons repel the valence shell electron to keep them loosely held with nucleus. it is thus evident that more is the shielding effect, lesser is the effective nuclear charge and lesser is the ionization energy. Q. Which of the following valence electron experience maximum effective nuclear charge?