Chemistry

Periodic Classification and Elements

1,092 Questions

Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.

Periodic table structureAtomic orbitalsElement identificationPeriodic laws

Periodic Classification and Elements Questions

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

The first periodic law stated by Mendeleev was :

  1. there is no correlation in the properties and atomic weights of the elements

  2. the properties of the elements are a periodic function of their atomic numbers

  3. the properties of the elements are a periodic function of their atomic weights

  4. the properties of the elements are a periodic function of their empirical formula
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The first periodic law stated by Mendeleev was, "the physical and chemical properties of the elements are a periodic function of their atomic weights (atomic masses)." The elements having similar properties appeared in the same group (vertical column).
Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

Which of the following is not a merit of Mendeleev's periodic table?

  1. It helped in correcting the atomic masses of some of the elements

  2. He predicted the properties of some undiscovered elements and left gaps for them

  3. He framed the periodic table with vertical and horizontal columns and gave shape to it

  4. He gave separate places to isotopes in his periodic table
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Merits of Mendeleev's periodic table:
1) It helped in correcting the atomic masses of some of the elements e.g. beryllium was corrected from 13.5 to 9. Similarly, indium, gold, platinum etc.
2) He predicted the properties of some undiscovered elements and left gaps for them e.g. Eka-boron, eka-aluminum and eka-silicon names were given for scandium, gallium, and germanium (not discovered at the time of Mendeleev).
3) He framed the periodic table with vertical and horizontal columns and gave shape to it.
4) Isotopes are the atoms of the same element having different atomic masses. Therefore, according to Mendeleev’s classification, these should be placed at different places depending upon their atomic masses. For example, hydrogen isotopes with atomic masses 1,2 and 3 should be placed at three places. However, isotopes have not been given separate places in the periodic table because of their similar properties.
Hence, option $D$ is correct.
Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

Nobel gases were included in Mendeleev's periodic table in the: 

  1. 1st group

  2. 7th group

  3. 8th group

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mendeleevs Periodic Table:
Elements are arranged in the periodic table in the increasing order of their relative atomic masses.
Mendeleev divided his periodic table in eight groups and seven periods.
Groups from I to VII are meant for normal elements and group VIII is for transition elements.
Groups from I to VII have been divided in two sub groups, while group VIII is meant for three elements.
Periods from 4th to 7th have been divided in two series: 1st series and 2nd series.
Elements having similar properties have been kept in the same group. For example; lithium, potassium, rubidium, etc. are in 1st group.

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

The number of elements known in Mendeleev's presented periodic table is:

  1. $50$
  2. $90$
  3. $63$
  4. $102$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

After the rejection of Newlands Octave Law, Mendeleev Periodic table came into existence. In Mendeleev’s periodic table, elements were placed based on the atomic mass, and chemical properties. During Mendeleev’s work, only 63 elements were found. After studying the properties of all elements, he found that the properties of elements were related to atomic mass.

Hence, the correct option is C.

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

According to Mendeleev's periodic law, the properties of elements are a periodic function of:

  1. atomic number.

  2. atomic weight.

  3. number of electrons.

  4. density.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In 1869, Dmitri Mendeleev and Lothar Meyer individually came up with their own periodic law "when the elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically." 


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

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

Two elements were elected by Mendeleev for studying the properties of compounds formed by other elements with the selected elements. What were the selected elements?

  1. Oxygen, Nitrogen

  2. Hydrogen, Carbon

  3. Hydrogen, Oxygen

  4. Oxygen, Carbon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The elements selected by Mendeleev were oxygen and hydrogen because most of the elements reacted with oxygen and hydrogen.

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

Eka-silicon was the name given by Mendeleev to the element similar to ________ in properties.

  1. Boron

  2. Germanium

  3. Aluminium

  4. Silicon
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The name given to the element, by Mendeleev, similar to Germanium in properties was Eka-Silicon.

Multiple choice chemistry the periodic table mendeleef's periodic table mendeleev's periodic law and its limitations mendeleev's periodic table development of the modern periodic table into the history

Which element was not known when Mendeleev gave his classification?

  1. Germanium

  2. Gallium

  3. Scandium

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The elements which were unknown when Mendeleev gave his classification were geranium, gallium and scandium. He left gaps for the unknown elements and predicted correctly the properties of some of the unknown elements.