Chemistry

Periodic Classification and Elements

1,176 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

The principal quantum number ‘n’ represents

  1. size of the orbital

  2. angular momentum of an electron

  3. shape of the orbital

  4. spin of the electron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The principal quantum number ‘n’ represents the size of the orbital.

Multiple choice

The element with the maximum electron affinity is

  1. N

  2. H

  3. He

  4. F
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. Halogens have the greatest electron affinity as by gaining one electron, they attain noble gas configuration. Thus, from the given elements, fluorine has the maximum electron affinity.

Multiple choice

The electronic configuration of chromium (Z = 24) is

  1. 1s2, 2s2, 2p6, 3s2, 3p6, 3d4, 4s2

  2. 1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1

  3. 1s2, 2s2, 2p6, 3s2, 3p6, 3d6, 4s0

  4. 1s2, 2s2, 2p6, 3s2, 3p6, 3d4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The electronic configuration of chromium (Z = 24) is 1s2, 2s2, 2p6, 3s2, 3p6, 3d5, 4s1.

Multiple choice

Which of the following properties was formulated by Mendeleev?

  1. The properties of elements are the periodic functions of their atomic radii.

  2. The properties of elements are the periodic functions of their atomic numbers.

  3. The properties of elements are the periodic functions of their atomic masses.

  4. The properties of elements are the periodic functions of the number of elements.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mendeleev stated the famous periodic law according to which, "Properties of elements are a periodic function of their atomic weights''. Mendeleev arranged elements in the increasing order of their atomic weights in the form of a table, which is known as Mendeleev's Periodic Table.

Multiple choice

Which of the following was the limitation of Newland’s law of octaves?

  1. Unlike elements were placed in the same slot.

  2. It was applicable only up to copper.

  3. It was assumed that only 10 elements exist in nature.

  4. Elements were arranged in triads.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The limitation of Newland’s Law of Octaves: In order to fit elements into his table, Newlands adjusted two elements in the same slot, but also kept some unlike elements under the same slot. Cobalt and nickel are in the same slot and are placed in the same column as fluorine, chlorine and bromine which have very different properties. Thus, Newlands Law of Octaves worked well with lighter elements only.