periodic table — BSSC Chemistry

50 Questions • 30 Minutes • Chemistry Mock Test in Hindi and English

Sample Questions from this Test

Question 1:

Who among the following grouped elements into sets of three based on similar chemical properties, known as the Law of Triads?
A.John Newlands
B.Dmitri Mendeleev
C.Johann Wolfgang Dobereiner
D.Henry Moseley

• Key Fact
In 1817, Johann Wolfgang Dobereiner grouped elements into triads based on similar chemical properties.

• Supporting Detail
The atomic mass of the middle element was approximately the average of the other two.

• Related Concept
This was the first scientific attempt to classify elements based on periodic properties.

• Why wrong options are wrong
Newlands gave Octaves, Mendeleev gave Atomic Mass periodicity, and Moseley gave Atomic Numbers.

• Exam Trick
Dobereiner = 'Tri'ads (Three).

• Additional Info
Only a few triads were found, so it failed for many elements.

Question 2:

Up to which element was Newlands' Law of Octaves applicable?
A.Potassium (K)
B.Calcium (Ca)
C.Scandium (Sc)
D.Thorium (Th)

• Key Fact
The Law of Octaves was applicable only up to calcium.

• Supporting Detail
After calcium, every eighth element did not possess properties similar to the first.

• Related Concept
It worked well only for lighter elements.

• Why wrong options are wrong
Options A, C, and D fall outside the specific boundary of this law's validity.

• Exam Trick
Remember "Newlands stopped at Milk (Calcium)".

• Additional Info
Newlands assumed only 56 elements existed in nature.

Question 3:

Consider the following statements regarding Mendeleev's Periodic Table:
1. He arranged elements in increasing order of their atomic numbers.
2. He left gaps for undiscovered elements and predicted their properties.
3. Eka-silicon was later discovered and named Germanium.
Which of the above statements is/are correct?
A.1 only
B.2 and 3 only
C.1 and 2 only
D.All of the above

• Key Fact
Mendeleev arranged elements in increasing order of atomic masses, not atomic numbers (Statement 1 is false).

• Supporting Detail
He predicted properties for undiscovered elements by leaving gaps.

• Related Concept
Eka-silicon's properties matched remarkably well with Germanium (Ge).

• Why wrong options are wrong
Atomic number concept was given later by Henry Moseley.

• Exam Trick
Mendeleev = Mass; Moseley = Number.

• Additional Info
Eka-aluminium was Gallium, and Eka-boron was Scandium.

Question 4:

Assertion (A): Modern periodic table places elements based on their atomic numbers.
Reason (R): Henry Moseley showed that the frequency of X-rays emitted by an element relates to atomic number rather than atomic mass.
A.Both A and R are true, and R is the correct explanation of A
B.Both A and R are true, but R is NOT the correct explanation of A
C.A is true but R is false
D.A is false but R is true

• Key Fact
The Modern Periodic Law states properties are periodic functions of atomic numbers.

• Supporting Detail
Henry Moseley's 1913 X-ray spectroscopy experiment proved this correlation.

• Related Concept
He observed a straight line plot of frequency vs atomic number (Z).

• Why wrong options are wrong
Therefore, the reason perfectly explains the assertion.

• Exam Trick
"Moseley's X-rays X-posed the Atomic Number."

• Additional Info
He corrected atomic masses to adjust placements based on properties.

Question 5:

In the modern periodic table, which blocks contain the representative elements?
A.s and p blocks
B.d and f blocks
C.s and d blocks
D.p and f blocks

• Key Fact
Elements of s and p-blocks are called representative elements.

• Supporting Detail
s-block contains Groups 1 and 2, while p-block contains Groups 13 to 18.

• Related Concept
d-block elements are transition elements, and f-block are inner transition elements.

• Why wrong options are wrong
Options containing d or f blocks refer to transition or inner transition elements.

• Exam Trick
'SP' (Super Power) elements represent the main table.

• Additional Info
Helium belongs to the s-block structurally but is placed with noble gases.

Question 6:

Match the following Groups with their common names:
(1) Group 1
(2) Group 2
(3) Group 17
(4) Group 18

(i) Halogens
(ii) Noble Gases
(iii) Alkali metals
(iv) Alkaline earth metals
A.1-iii, 2-iv, 3-i, 4-ii
B.1-iv, 2-iii, 3-ii, 4-i
C.1-iii, 2-i, 3-iv, 4-ii
D.1-ii, 2-iii, 3-i, 4-iv

• Key Fact
Group 1 elements are Alkali metals, Group 2 are Alkaline earth metals, Group 17 are Halogens, and Group 18 are Noble gases.

• Supporting Detail
Alkali metals form strong basic hydroxides in water.

• Related Concept
Group 16 elements are called Chalcogens (ore-forming elements).

• Why wrong options are wrong
Any other matching incorrects the standard group naming convention.

• Exam Trick
"Alkali comes before Alkaline" (Group 1 before Group 2).

• Additional Info
Group 15 elements are known as Pnictogens.

Question 7:

Which of the following non-metals is liquid at room temperature?
A.Mercury (Hg)
B.Bromine (Br)
C.Francium (Fr)
D.Gallium (Ga)

• Key Fact
Bromine is the only liquid non-metal at room temperature.

• Supporting Detail
Mercury is a liquid metal, not a non-metal.

• Related Concept
Gallium and Caesium are metals that liquefy just above room temperature.

• Why wrong options are wrong
Carefully reading "non-metal" eliminates Mercury and Gallium.

• Exam Trick
Br = "Bro, it's liquid and non-metal!".

• Additional Info
Bromine belongs to Group 17 (Halogens).

Question 8:

Which property does NOT show any trend on moving from one side to the other in the periodic table?
A.Electronegativity
B.Valency
C.Radioactivity
D.Atomic Size

• Key Fact
Radioactivity does not show a specific periodic trend across a period in the periodic table.

• Supporting Detail
It depends purely on nuclear stability (neutron-to-proton ratio) rather than electron configuration.

• Related Concept
Atomic size decreases, electronegativity increases, and valency fluctuates in a set pattern across a period.

• Why wrong options are wrong
Options A, B, and D are classical electronic periodic properties.

• Exam Trick
Radioactivity is a nuclear property, independent of periodic electronic trends.

• Additional Info
Examples of radioactive elements include Uranium, Radium, and Thorium.

Question 9:

Arrange the following historical classification methods in chronological order:
1. Mendeleev's Periodic Table
2. Modern Periodic Table
3. Dobereiner's Triads
4. Newlands' Law of Octaves
A.3, 4, 1, 2
B.4, 3, 1, 2
C.3, 1, 4, 2
D.1, 4, 3, 2

• Key Fact
Dobereiner (1817) → Newlands (1865) → Mendeleev (1869) → Modern Periodic Table / Moseley (1913).

• Supporting Detail
Dobereiner grouped elements in threes; Newlands used musical octaves; Mendeleev arranged by atomic mass.

• Related Concept
Moseley shifted the classification basis from atomic mass to atomic number.

• Why wrong options are wrong
Any other arrangement violates the chronological sequence of development.

• Exam Trick
Remember D-N-M-M (Dobereiner, Newlands, Mendeleev, Modern).

• Additional Info
All early methods were based on atomic mass; only modern is based on atomic number.

Question 10:

Statement 1: The atomic radius decreases down a group due to increased nuclear charge.
Statement 2: Ionization energy decreases down a group as the outermost electrons are farther from the nucleus.
Which of the above is/are correct?
A.Only Statement 1
B.Only Statement 2
C.Both 1 and 2
D.Neither 1 nor 2

• Key Fact
Statement 1 is false: Atomic radius INCREASES down a group because new electron shells are added.

• Supporting Detail
Statement 2 is true: Ionization energy decreases down a group due to lower nuclear attraction on farther electrons.

• Related Concept
Down a group, shielding effect overpowers nuclear charge increase.

• Why wrong options are wrong
Since statement 1 is factually wrong, options selecting 1 are incorrect.

• Exam Trick
Size goes UP down the group; Energy required to pull an electron goes DOWN.

• Additional Info
The largest atomic size in a period belongs to the Alkali Metals.

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