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

In s-block, electrons are filled in the

  1. p orbital

  2. s orbital

  3. d orbital

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

At any given moment, an electron can be found at any distance from the nucleus and in any direction according to the Heisenberg Uncertainty Principle. The s orbital is a spherically-shaped region describing where an electron can be found, within a certain degree of probability. The shape of the orbital depends on the quantum numbers associated with an energy state. All s orbitals have l = m = 0, but the value of n can vary.

Multiple choice

The shortest period of the periodic table is

  1. 1st period

  2. 5th period

  3. 6th period

  4. 7th period
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The shortest period of the periodic table is the 1st period .It contains only 2 elements which are Hydrogen and Helium.

Multiple choice

The number of electrons in the valence shell signifies

  1. group number

  2. period number

  3. atomic density

  4. atomic volume
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The group number is the number assigned to the vertical columns of the structured list of all known elements in the periodic table. Elements within the same group have the same number of electrons in their outer electron shells.

Multiple choice

Elements placed on the extreme right of the periodic table are known as

  1. Noble gases

  2. Alkali metals

  3. Transition metals

  4. Inner transition metals
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The noble gases, also known as the inert gases, are located in Group VIII of the periodic table. Group VIII is sometimes called Group O. The noble gases are helium, neon, argon, krypton, xenon, radon, and ununoctium.The noble gases are relatively nonreactive. This is because they have a complete valence shell. The noble gases have low boiling points and  all are gases at room temperature.The noble gases are on the extreme right of the periodic table.

Multiple choice

What determines the properties of an element in the periodic table?

  1. Number of protons

  2. Electronic configuration

  3. Atomic number

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

The distribution of electrons in different orbitals is known as its electronic configuration. This characterizes each electron in an atom. The electronic configuration is expressed by indicating the principal quantum number and its respective orbital along with the number of electrons present in it. For example, the notation 3px1 indicates that in the third principal shell there is one electron in the 'px' orbital.

Multiple choice

The cause of periodicity in the periodic table is

  1. atomic orbitals

  2. atomic mass

  3. atomic number

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

 The recurrence of characteristic properties of elements, arranged in the periodic table at regular intervals, is called periodicity. Elements having similar electronic configuration have similar properties. Thus the cause of periodicity is the repetition of similar electronic configuration.

Multiple choice

Which group has zero valency?

  1. 1st group

  2. 8th group

  3. 2nd group

  4. 3rd group
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The extreme right elements have 8 electrons in their valence shell (except Helium which has 2, a duplet). Their valence shell being completely filled, their octet is satisfied and they do not take part in chemical reactions. Hence their valency or combining power is zero.

Multiple choice

Valence shell electrons refers to the

  1. electrons present in the nucleus

  2. electrons present in the innermost shell

  3. electrons present in the outermost shell

  4. electrons present outside the valence shell
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Valence shell electrons are the electrons in the outermost shell .