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

In the modern periodic table, the elements of a group have similar properties because they have the same

  1. atomic number

  2. atomic weight

  3. number of valence electrons

  4. electronic configuration

  5. number of neutrons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The properties of an element depend on the valence electrons or the number of electrons in the outermost orbit. In a group of modern periodic table, all the elements have the same number of valence electrons. For example, all alkali elements have one electron in their outermost orbit. Hence, they have similar properties.

Multiple choice

An atom A is in period 3 and group 16(VI A) of the periodic table. Which of the following statements is correct?

  1. It is a metal.

  2. It is a non-metal.

  3. It is a metalloid.

  4. None of these

  5. Cannot be predicted

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The mentioned element should have 3 shells and 6 valence electrons in the outermost shell. It must gain two electrons to attain a stable electronic configuration of 8 electrons in the outermost shell. Such elements which tend to gain one or more electrons are non-metals, so the mentioned element must be a non-metal.

Multiple choice

Which of the following statements is/are correct?

a. Joseph L. Proust was the first scientist to use the symbols for elements in a very specific sense. b. Dalton suggested that the symbols of elements be made from one or two letters of the name of the element. c. IUPAC approves the names of the elements.

  1. a only

  2. b only

  3. c only

  4. a and b

  5. a and c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

IUPAC (International Union of Pure and Applied Chemistry) approves the names of the elements. 

Multiple choice

How does ionisation energy change as we go down a group in the modern periodic table?

  1. Increases

  2. Decreases

  3. No change

  4. First increases and then decreases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionisation energy goes on decreasing down a group. It is due to increase in the distance between the valence electrons and the nucleus. As the atomic size increases down a group, the force of attraction between the nucleus and the valence electrons decreases. Therefore, the energy required to remove the electrons, i.e. ionisation energy, goes on decreasing.