NEET Test Series from KOTA - 10 Papers In MS WORD
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THE d-AND f-BLOCK ELEMENTS
16152
The lanthanide contraction is responsible for the fact that
1 \(Zr\) and \(Y\) have about the same radius
2 \(Zr\) and \(Nb\) have similar oxidation state
3 \(Zr\) and \(Hf\) have about the same radius
4 \(Zr\) and \(Zn\) have the same oxidation state
Explanation:
Due to lanthanide contration the size for \(Zr\) and \(Hf\) is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order \(s\,>\,p\,>\,d\,>\,f\). This \(f\) subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like \(Hf, 4 f\) subshell is filled and it is not very effective at shielding the outer shell ( \(n =5\) and \(n =6\) ) electrons. it is similar to \(Zr\).
THE d-AND f-BLOCK ELEMENTS
16153
The number of unpaired electrons in \(C{r^ + }\) will be
1 \(3\)
2 \(4\)
3 \(5\)
4 \(6\)
Explanation:
(c)
THE d-AND f-BLOCK ELEMENTS
16154
The highest oxidation state of \(Cr\) will be
1 \(2\)
2 \(3\)
3 \(4\)
4 \(6\)
Explanation:
(d)There are \(6\) electrons in its ultimate and penultimate shell.
THE d-AND f-BLOCK ELEMENTS
16155
Which statement is true about the transitional elements
1 They are highly reactive
2 They show variable oxidation states
3 They have low M.P.
4 They are highly electropositive
Explanation:
(b)They show variable oxidation state due to participation of \(ns\) and \((n - 1)d\) electrons.
16152
The lanthanide contraction is responsible for the fact that
1 \(Zr\) and \(Y\) have about the same radius
2 \(Zr\) and \(Nb\) have similar oxidation state
3 \(Zr\) and \(Hf\) have about the same radius
4 \(Zr\) and \(Zn\) have the same oxidation state
Explanation:
Due to lanthanide contration the size for \(Zr\) and \(Hf\) is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order \(s\,>\,p\,>\,d\,>\,f\). This \(f\) subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like \(Hf, 4 f\) subshell is filled and it is not very effective at shielding the outer shell ( \(n =5\) and \(n =6\) ) electrons. it is similar to \(Zr\).
THE d-AND f-BLOCK ELEMENTS
16153
The number of unpaired electrons in \(C{r^ + }\) will be
1 \(3\)
2 \(4\)
3 \(5\)
4 \(6\)
Explanation:
(c)
THE d-AND f-BLOCK ELEMENTS
16154
The highest oxidation state of \(Cr\) will be
1 \(2\)
2 \(3\)
3 \(4\)
4 \(6\)
Explanation:
(d)There are \(6\) electrons in its ultimate and penultimate shell.
THE d-AND f-BLOCK ELEMENTS
16155
Which statement is true about the transitional elements
1 They are highly reactive
2 They show variable oxidation states
3 They have low M.P.
4 They are highly electropositive
Explanation:
(b)They show variable oxidation state due to participation of \(ns\) and \((n - 1)d\) electrons.
16152
The lanthanide contraction is responsible for the fact that
1 \(Zr\) and \(Y\) have about the same radius
2 \(Zr\) and \(Nb\) have similar oxidation state
3 \(Zr\) and \(Hf\) have about the same radius
4 \(Zr\) and \(Zn\) have the same oxidation state
Explanation:
Due to lanthanide contration the size for \(Zr\) and \(Hf\) is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order \(s\,>\,p\,>\,d\,>\,f\). This \(f\) subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like \(Hf, 4 f\) subshell is filled and it is not very effective at shielding the outer shell ( \(n =5\) and \(n =6\) ) electrons. it is similar to \(Zr\).
THE d-AND f-BLOCK ELEMENTS
16153
The number of unpaired electrons in \(C{r^ + }\) will be
1 \(3\)
2 \(4\)
3 \(5\)
4 \(6\)
Explanation:
(c)
THE d-AND f-BLOCK ELEMENTS
16154
The highest oxidation state of \(Cr\) will be
1 \(2\)
2 \(3\)
3 \(4\)
4 \(6\)
Explanation:
(d)There are \(6\) electrons in its ultimate and penultimate shell.
THE d-AND f-BLOCK ELEMENTS
16155
Which statement is true about the transitional elements
1 They are highly reactive
2 They show variable oxidation states
3 They have low M.P.
4 They are highly electropositive
Explanation:
(b)They show variable oxidation state due to participation of \(ns\) and \((n - 1)d\) electrons.
16152
The lanthanide contraction is responsible for the fact that
1 \(Zr\) and \(Y\) have about the same radius
2 \(Zr\) and \(Nb\) have similar oxidation state
3 \(Zr\) and \(Hf\) have about the same radius
4 \(Zr\) and \(Zn\) have the same oxidation state
Explanation:
Due to lanthanide contration the size for \(Zr\) and \(Hf\) is same. Lanthanide contraction can be explained on the basis of shielding effect.In multi-electron atoms the electrons are added in outer shells. The electrons already present in inner shells, shield the outer electrons from nuclear charge, making them experience a lower effective charge of the nucleus. The shielding effect exerted by the inner electrons decreases in the order \(s\,>\,p\,>\,d\,>\,f\). This \(f\) subshell poorly shields the outer electron from nuclear attraction which results in more attractive pull of nucleus on outer electron and smaller size.In case of post lanthenide elements like \(Hf, 4 f\) subshell is filled and it is not very effective at shielding the outer shell ( \(n =5\) and \(n =6\) ) electrons. it is similar to \(Zr\).
THE d-AND f-BLOCK ELEMENTS
16153
The number of unpaired electrons in \(C{r^ + }\) will be
1 \(3\)
2 \(4\)
3 \(5\)
4 \(6\)
Explanation:
(c)
THE d-AND f-BLOCK ELEMENTS
16154
The highest oxidation state of \(Cr\) will be
1 \(2\)
2 \(3\)
3 \(4\)
4 \(6\)
Explanation:
(d)There are \(6\) electrons in its ultimate and penultimate shell.
THE d-AND f-BLOCK ELEMENTS
16155
Which statement is true about the transitional elements
1 They are highly reactive
2 They show variable oxidation states
3 They have low M.P.
4 They are highly electropositive
Explanation:
(b)They show variable oxidation state due to participation of \(ns\) and \((n - 1)d\) electrons.
