SSC CGL Science – Periodic Table & Chemical Bonding – Level 2 · Exam Level · Tier I Sprint

← Back

SSC CGL Science – Periodic Table & Chemical Bonding – Level 2 · Exam Level · Tier I Sprint – 15 questions, subject: General Science. Every question has the correct answer with a one-line explanation; tap "Show Answer". Free practice for TNPSC, UPSC, SSC, Bank and RRB exams – Shanmugam IAS Academy, Coimbatore.

Get daily current affairs & exam alerts – follow us YouTube WhatsApp Channel Telegram Channel Facebook Page Instagram
Share with friends & study groups
Link to this page from your website / blog (HTML code)
1.  
The element with atomic number 20 is placed in:

Correct Answer: B [period 4, group 2]

Explanation:

2, 8, 8, 2 → 4 shells (period 4), 2 valence electrons (group 2).

2.  
The formula of calcium phosphate is:

Correct Answer: A [Ca₃(PO₄)₂]

Explanation:

Ca²⁺ and PO₄³⁻: swap 2 and 3 → Ca₃(PO₄)₂.

3.  
In the triad sulphur (32), selenium, tellurium (127.6), the expected atomic mass of selenium by Döbereiner's rule is:

Correct Answer: C [79.8]

Explanation:

(32 + 127.6) ÷ 2 = 79.8 (actual about 79).

4.  
Match the followingMatch the group with its family:
P. Group 1 Q. Group 17 R. Group 18
1. Noble gases 2. Halogens 3. Alkali metals

Correct Answer: D [P-3, Q-2, R-1]

Explanation:

1 – alkali metals; 17 – halogens; 18 – noble gases.

5.  
Chronological orderChronological order (earliest first):
1. Mendeleev's table 2. Döbereiner's triads 3. Moseley's atomic number 4. Newlands' octaves

Correct Answer: D [2, 4, 1, 3]

Explanation:

Döbereiner (1817–29) → Newlands (1860s) → Mendeleev (1869) → Moseley (1913).

6.  
Odd one outOdd one out (not a halogen):

Correct Answer: C [Sulphur]

Explanation:

Sulphur is in group 16; the rest are group 17.

7.  
Assertion–Reason
A: Ionic compounds have high melting points.
R: Strong electrostatic forces hold the oppositely charged ions together.

Correct Answer: A [Both A and R are true and R explains A]

Explanation:

Much energy is needed to break strong ionic attractions.

8.  
Which of these atoms has the largest atomic radius?

Correct Answer: B [K]

Explanation:

K is lowest (period 4) and leftmost (group 1) – down-left grows.

9.  
Two-quantity comparison
Quantity I: number of shared electron pairs in CO₂
Quantity II: number of shared electron pairs in CH₄

Correct Answer: C [Quantity I = Quantity II]

Explanation:

CO₂: O=C=O → 4 pairs; CH₄: four C–H → 4 pairs.

10.  
A coordinate (dative) bond is present in:

Correct Answer: D [the ammonium ion, NH₄⁺]

Explanation:

NH₃ donates its lone pair to H⁺ to form NH₄⁺.

11.  
Which family of elements is missing from Mendeleev's original table of 1869, because none of its members had yet been discovered?

Correct Answer: A [noble gases]

Explanation:

Argon was found only in 1894 and the other noble gases soon after; they were added later as a new group.

12.  
Spot My Mistake“Aluminium oxide: Al³⁺ and O²⁻; criss-cross gives Al₃O₂.” The correct formula is:

Correct Answer: B [Al₂O₃]

Explanation:

Al takes O's valency (2) and O takes Al's (3): Al₂O₃.

13.  
True/false countHow many of these statements are true?
I. Ionic compounds conduct electricity in the solid state.
II. Covalent compounds generally have low melting points.
III. Hydrogen bonding makes ice less dense than water.
IV. Metallic bonding involves a ‘sea’ of free electrons.

Correct Answer: B [3]

Explanation:

Only I is false – ionic solids conduct only when molten or dissolved.

14.  
Which of the following oxides is amphoteric?

Correct Answer: A [Al₂O₃]

Explanation:

Al₂O₃ reacts with both acids and bases; Na₂O, MgO basic; SO₃ acidic.

15.  
An element with electronic configuration 2, 8, 8, 1 belongs to:

Correct Answer: D [period 4, group 1]

Explanation:

4 shells → period 4; 1 valence electron → group 1 (potassium).

➤ Full notes, shortcuts and every answer explained – SSC CGL 2026 General Science book (₹149): www.shanmugamiasacademy.in/study-materials/ssc-cgl-general-science

📘 SSC CGL 2026 – General Science (Tier I + Tier II)
Here you get the answer with a one-line explanation. 1,110 original questions with answer key and explanations · mind-maps, notes, tables and shortcuts · Tier I and Tier II practice sets + 3 mock tests
Get the book – ₹149 ₹299 →
Score: 0 Answered: 0 / 0