Tag: the periodic table

Questions Related to the periodic table

Mendeleev arranged the elements in increasing order of their atomic masses and according to their physical properties.

  1. True

  2. False


Correct Option: B
Explanation:

In 1869, just five years after Newlands put forward his Law of Octaves, a Russian chemist called Dmitri Mendeleev published a periodic table. Mendeleev also arranged the elements known at the time in order of relative atomic mass, but he did some other things that made his table much more successful. Hence he arranged according to atomic masses and their chemical properties.

Noble gases were included in Mendeleev's periodic table in :

  1. 1st group

  2. 7th group

  3. 8th group

  4. none of the above


Correct Option: D
Explanation:

In the Mendeleev's periodic table, the noble gases were included in the zeroth group.

Which scientist came up with the concept of a periodic table that included all of the known elements?

  1. Joseph Priestly

  2. Dmitri Mendeleev

  3. Antoine Lavoisier

  4. Albert Einstein


Correct Option: B
Explanation:

Dmitri Mendeleev is credited with designing the modem periodic table. Joseph Priestly and Antoine Lavoisier were both chemists. Albert Einstein developed theories on photoelectric effect.

Isotopes could find a position in Mendeleev's periodic table.
State whether the given statement is true or false.

  1. True

  2. False


Correct Option: B
Explanation:

Isotopes could not find a position in Mendeleev's periodic table because those were arranged according to atomic number in the increasing order but isotopes have the same atomic number, all isotopes cannot be fitted in a single box in the periodic table. Hence, given statement is false.

Which of the following is(are) the merit(s) of Mendeleev's periodic table?
  1. Could also predict the properties of these unknown elements

  2. Grouping of chemically dissimilar elements.

  3. Position given to isotopes.

  4. Presence of anomalous pairs.


Correct Option: A
Explanation:
A)Mendeleev could also predict the properties of these unknown elements, on the basis of the properties of the elements lying adjacent to these vacant spaces.

He predicted the presence of three elements. They were named as Eka boron, Eka-aluminium and Eka-silicon. The properties of these three elements were similar to the actual elements discovered later.

Eka-boron was similar to Scandium, Eka-aluminium was similar to Gallium and Eka-silicon was similar to Germanium.

It is the merit of Mendeleev's periodic table and all other options are demerits of it.

B) Some elements placed in the same sub-group varies in the properties. 
     Ex. Manganese is placed with halogens which totally differ in properties.

C) Isotopes had to be given the same position though isotopes of the same elements have different atomic masses.

D) The element of higher atomic mass ex. Cobalt [58.93u] has been placed before an element of lower atomic mass ex. Nickel [58.71u]. 
     These are anomalous pairs.

Hence, the correct option is $\text{A}$

Which among the following is not an anomalous pair in Mendeleev's periodic table?

  1. Co, Ni

  2. Te, I

  3. Ar, K

  4. Sc, Ga


Correct Option: D
Explanation:

In certain pair of elements, the increasing order of atomic masses was not obeyed. 


In these, Mendeleev placed elements according to similarities in their properties and not in increasing order of their atomic masses.

 The last pair is not anomalous pair.

Option D is correct.

The chemical formula of the oxide of $Eka\ -$ aluminium is:

  1. $GaO$

  2. $GaO _2$

  3. $Ga _2O _2$

  4. $Ge _2O _3$


Correct Option: D
Explanation:

$Eka$-aluminium is known as $Gallium$.


Gallium forms only two oxides as ${Ga} _{2}O$ or ${Ga} _{2}{O} _{3}$.

It's is in $+1$ and $+3$ oxidation state$.$.

Therefore, the correct option is $D$.

Cycloalkanes are isomeric with

  1. Alkenes

  2. Alkanes

  3. Alkynes

  4. Arenes


Correct Option: A
Explanation:

Cycloalkanes are isomeric with alkenes because they have the same general formula CnH2n but possessing different structures, shows ring chain isomerism. Example- cyclohexane $(C _6H _12)$ and hexene $(C _6H _12)$ are ring chain isomers.

The first element of a group in many ways differs from the other heavier members of the group. This is due to:

  1. the small size

  2. the high electronegativity and high ionisation potential

  3. the unavailability of d-orbitals

  4. all of the above


Correct Option: D
Explanation:

1st element of a group, have smaller size and high IP, also they dont have d-orbitals so they show different properties like valency, ionic character, maximum valency solubility.

Write the correct alternatives :
According to Mendeleev's periodic law, properties of elements are periodic function of their...............

  1. Atomic number

  2. Atomic masses

  3. Densities

  4. Boiling points


Correct Option: B
Explanation:

According to Mendeleev's law, the physical and chemical properties of element are the periodic function of their atomic weights . (atomic masses)


$\therefore$ option "B" is correct.