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

How does the non-metallic character of elements vary on moving down a group?

  1. Decreases

  2. Increases

  3. Remains same

  4. Varies according to a particular period
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atoms showing tendency to gain one or more electrons is said to be non-metallic. On moving down a group, the atomic radii of atoms increase. This results in less effective attraction from nucleus side for the electrons in the outermost shell. So, down the group, the tendency to lose electrons increases, while the tendency to gain electrons is reduced. Hence, the non-metallic character decreases as we go down a group.

Multiple choice

An atom is said to be non-metal, if :

  1. it loses one or more electrons

  2. it gains one or more electrons

  3. it has more number of electrons than protons

  4. it has lesser number of electrons than protons
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An atom is said to be non-metallic if it gains one or more electrons when supplied with energy.

Multiple choice

The electron affinity, on moving from group 1 to group 7 :

  1. decreases then increases

  2. decreases

  3. increases

  4. does not change
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 Moving from group 1 to group 7, i.e., along a period from left to right, there occurs an increase in nuclear charge as well as decrease in atomic size. Both these factors make the electrons tightly bound towards the nucleus, thus making it difficult for them to be lost. This increases the electron affinity.

Multiple choice

The group number of an element is equal to:

  1. the total number of electrons in its atom

  2. the total number of protons in its atom

  3. total number of electrons and protons in an atom of the element

  4. the total number of electrons in outermost shell
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The total number of electrons present in the outermost shell of an atom represents the group number of the element.

Multiple choice

The atomic size of elements on moving from left to right in a period :

  1. decreases

  2. increases

  3. first decreases then increases

  4. remains same
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

There is increase in atomic no. as well as nuclear charge of the atoms of the elements when we go from left to right in a period. But, no new shell is added, which means more number of protons attracts the electrons present at the same distance from them. So there is a decrease in radius or atomic size of the atoms.

Multiple choice

Elements of the same period have:

  1. same electronic configuration

  2. same number of electrons in the outermost shell

  3. same number of electronic shells

  4. same atomic size
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Number of period is equal to the number of shells occupied by the electrons of an atom in its ground state. So, the elements having same no. of electronic shells when their electronic configuration is represented in their respective ground states are placed in the same period.

Multiple choice

The elctronegativity of elements on moving left to right of the periodic table:

  1. depends on the valence electrons

  2. remains same

  3. decreases

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

As we move from left to right, decrease in atomic size and increase in nuclear charge of an atom occurs. So, the electrons present in the same number of shells (same period) are pulled more effectively towards the nucleus, and hence increase in electro negativity.

Multiple choice

The most electronegative element of the periodic table is:

  1. hydrogen

  2. fluorine

  3. helium

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

Fluorine (atomic no. 9) has only two shells in its atomic state with 7 electrons in its outermost shell. So, it it tends to gain one electron to become stable. The 7 protons present in the nucleus and small size of the atom make it possibly the most electronegative element of the periodic table.

Multiple choice

Which of the following has the least number of shells?

  1. Na

  2. K

  3. Li

  4. All of them have equal no. of shells.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Li occurs at the top of the alkali metals group. Number of shells increases down a group. So, Li is smallest with least no. of shells, with Na and K following the order.

Multiple choice

The element with largest atomic size in period 2 is:

  1. boron

  2. nitrogen

  3. fluorine

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

On moving from left to right, the atomic size decreases due to increase in effective nuclear charge. From amongst the given elements, these occur in period 2 of periodic table in the order- beryllium, boron, nitrogen and fluorine (atomic numbers 4, 5, 7 and 9 respectively). Thus, atomic size decreases from beryllium to fluorine. Hence, beryllium has largest atomic size amongst the given elements.