Valency and Oxidation States

Q.

The oxidation number of $\mathrm{Pt}$ in the complex ${\left[\mathrm{Pt}\right({\mathrm{C}}_2{\mathrm{H}}_4\left){\mathrm{Cl}}_3\right]}^{-}$is_.

Q.

Acidic Character decreases along a period from left to right?

1. True

2. False

Q.

In which of the following arrangements the order is NOT according to the property indicated against it

1. Al³<Mg²⁺<Na+<F^-: Increasing ionic size

2. B<C<N<O: Increasing first ionization enthalpy

3. I<Br<F<Cl: Increasing electron gain enthalpy (with negative sign)

4. Li<Na<K<Rb: Increasing metallic radius

Q.

The electronic configuration of four elements are given below.

Which elements does not belong to same family as others

1. [xe] 4f¹⁴ 5d¹⁰6s²

2. [kr] 4d¹⁰5s²

3. [Ne] 3s² 3p⁵

4. [Ar] 3d¹⁰ 4s²

Q. 10. Oxidation state of each boron in borax And the most unstable hydride of boron family?

Q. More will be the electron density, more will be the basic nature.Explain why?How the basic nature depends on electron density?

Q. Why do elements in the same group have similar physical and chemical properties?

Q. 38. An element has electronic configuration 1s2, 2s2 2p6, 3s2 3p2. Its valency electron are?

Q. Second ionization potential of oxygen is

1. Half of that of fluorine
2. Equal to that of fluorine
3. Less than that of fluorine
4. Greater than that of fluorine

Q. 7.Explain the comparison of oxidative property of Sn4+ and Sn2+ ions on the basis of inert pair effect

Q. What is the oxidative state of Fe0.94o

Q. Which metal exhibits more than one oxidation states in their compounds.

1. $Na$
2. $Mg$
3. $Al$
4. $Fe$

Q.

An element A in a compound ABD has oxidation number A^n-. It is oxidised by $C{r}_2{O}_7^{-}2$ in acid medium. In the experiment 1.68$\times$${10}^{-}3$ x moles of$K_{2}C{r}_2{O}_7$ were used for 3.26$\times$${10}^{-}3$ moles of ABD. The new oxidation number of A after oxidation is:

1. 3

2. 3-n

3. n-3

4. +n

Q. Oxidation state of Oxygen in $K{O}_2$ is

1. -2

2. 

3. +2

4. 

Q. The oxide in the higher oxidation state of the element is more acidic than that of lower oxidation state. Why?

Q. Who used the physical properties of elements such as melting point, boiling point and atomic volume etc. for the classification of elements?

1. John Alexander Newlands
2. Lothar Meyer
3. Wolfgang Dobereiner
4. Dmitri Ivanovich Mendeleev

Q. why lithium has highest hydration enthalp

Q. a compound contains atoms of three elements a, b, c. if the oxidation no. of a=+2, b=+5, c=-2 the possible formula of the compound is ? how?

Q. The species that contains 24 protons, 26 neutrons and 22 electrons would be represented by the symbol:

1. ${}^{50}{V}^{3+}$
2. ${}^{26}C{r}^{2+}$
3. ${}^{50}C{r}^{2+}$
4. ${}^{26}M{n}^{2+}$

Q. Why lithium has the highest reducing nature in aqueous solution wherease normally in air it has lowest reducing nature?

Q. Select the correct option for the below statements:
Statement I: $P{b}^{4+}$ compounds are stronger oxidizing agents than $S{n}^{4+}$compounds.
Statement II: The higher oxidation states for the group $14$ elements are more stable for the heavier members of the group due to the ‘inert pair effect’.

1. Statement I is true; Statement II is true; Statement II is the correct explanation of Statement I.
2. Statement I is true; Statement II is true; Statement II is not the correct explanation of Statement I.
3. Statement I is true; Statement II is false.
4. Statement I is false; Statement II is true.

Q. The number of valence electrons in the elements A and B are 3 and 6 respectively. The most probable compound formed from A and B is:

1. $A_{2}B$
2. $A{B}_2$
3. $A_6{B}_3$
4. $A_2{B}_3$

Q.

Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?

1. Principal quantum number (n).
2. Nuclear charge (Z).
3. Nuclear mass.
4. Number of core electrons.

Q. arrange the following cationsin the order of increasing polarising power

1. zn+2, cd+2, hg+2
2. cu+, ag+, au+, au+3

Q.

why s2- has larger radius then cl-?

Q. 29.meaning of oxidising agent

Q. Which of the following statements is not true for halogens?

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> NEET 2018

1. All form monobasic oxyacids
2. All are oxidizing agents
3. Chlorine has the highest electron-gain enthalpy
4. All but fluorine show positive oxidation states

Q.

why florine does not show disproportionation reaction

Q. 6 when ClO can act as oxidising agents then how can Cl, I, Br can act as oxidising agents in dispropotionation reactions then why cant Flourine because according to this reaction a element must exist in its intermediate form?

Q.

Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?

1. Principal quantum number (n).
2. Nuclear charge (Z).

3. Nuclear mass.

4. Number of core electrons.